CN101969729A - Discharge lamp lighting apparatus - Google Patents

Abstract

The invention provides a discharge lamp lighting apparatus, which can promote the elimination of asymmetric discharging state and ensure a reliable lighting performance when a high-intensity discharge lamp is starts. In a starting sequence of a discharge lamp, the resonance frequency of a resonance circuit drives an inverter; a power supply circuit outputs non-load open circuit voltage. If a discharge lamp is broken down to start discharging, the frequency of the inverter descends gradually from the resonant frequency to the first threshold frequency; when the frequency reaches the first threshold frequency, the frequency of the inverter is converted into a stable lighting frequency, and is controlled to cause the power supply circuit to output a current sufficient to maintain electric discharge.

Description

Lighting apparatus for discharge lamp

Technical field

The present invention relates to be used to light high-pressure discharge lamp, especially light the lighting apparatus for discharge lamp of high brightness discharge lamps such as high-pressure mercury-vapor lamp, metal halide lamp, xenon lamp.

Background technology

Being used for the light supply apparatus that liquid crystal projector for example, the such image of DLP (TM) projector show the Optical devices of using etc., use high-intensity discharge lamp (HID lamp).In above-mentioned projector, adopted following manner: wait by dichroic prism and separate R, G, this 3 primary colors of B, by the image that produces each 3 primary colors at the spatial modulation element that is provided with of all kinds respectively is set, come color display by synthetic once more light paths such as dichroic prisms.In addition, in other modes, make have R, the rotation of the colour filter of G, B 3 primary colors, make light pass through this colour filter from light source, produce the light beam of each 3 primary colors thus successively, by making these light beams synchronously and control the spatial modulation element, produce the image of each 3 primary colors successively with the time partitioning scheme, thus color display.

The type of drive of the discharge lamp during about constant lighting has DC driven mode and AC driving mode, and this AC driving mode is come periodically reversed polarity by also possessing converter (inverter).Under the situation of DC driven mode, have following significant advantage: the light beam from lamp also is a direct current, promptly can time to time change, in the mode of above-mentioned two projectors, can be suitable for basically identically.To this, under the situation of AC driving mode, have following advantage: utilize the degree of freedom that does not have in the DC driven mode that is called as the polarity inversion frequency, the consumption that might be able to control electrode for discharge lamp becomes growth.

Under the situation of starting this kind lamp, after applying to lamp under the state that is called as the non-loaded voltage of opening voltage, applying high voltage, in discharge space, produce insulation breakdown, change arc discharge into through after the glow discharge.Under the situation of AC driving mode, as the method for reaching aforesaid way, from in the past, back grade of series resonant circuit that is provided with based on resonant inductor and resonant capacitor at converter, when starting, produce the series resonance phenomenon, improve the resonance starting of the series resonance mode of the voltage that applies to lamp so that the polarity frequency of converter and the resonance frequency of this resonant circuit match.In addition, by the also usefulness of this resonance starting and igniter (igniter), improve starting probability thereby can improve the high-tension peak value that is applied.

Figure 18 has represented the formation of a mode of lighting apparatus for discharge lamp in the past with simplifying, is the figure that is used to illustrate the principle relevant with the resonance starting.The lighting apparatus for discharge lamp of this figure possesses: to the power supply circuits (Ux ') of discharge lamp (Ld) power supply; Be used to make the converter (Ui ') of the full-bridge type of this output voltage polarity inversion; Resonant inductor (Lh '); And resonant capacitor (Ch '), when starting, with the resonance frequency determined by the long-pending value of the electrostatic capacitance of the inductance of above-mentioned resonant inductor (Lh ') and above-mentioned resonant capacitor (Ch ') or near this frequency of thanking to vibration frequency above-mentioned converter (Ui ') is carried out polarity inversion and drive, between the two-terminal of above-mentioned resonant capacitor (Ch '), produce high voltage by the LC series resonance phenomenon that produces thus, thereby apply high voltage to above-mentioned discharge lamp (Ld).

When series resonance is moved, though in order not make the resonance current that flows through above-mentioned converter (Ui ') excessive, need reduce the electrostatic capacitance of resonant capacitor and increase the inductance of resonant inductor to a certain extent, but this inductance is big more, and the moment of the easy more beam of light when occurring in constant lighting disconnects, overshoot (overshoot) or vibration.And, in the series resonance mode, in order to make the voltage that applies to lamp obtain enough risings, the frequency of the resonance frequency that the frequency setting of the frequency of periodic voltage applying unit or this high order harmonic component composition promptly need be tuned as resonant circuit for the frequency with the odd-multiple of the resonance frequency of resonant circuit or resonance frequency matches or the odd-multiple of resonance frequency.

Yet, because parts there are differences (バ ラ Star キ), therefore there is following problem: drive even above-mentioned converter (Ui ') is carried out polarity inversion with predefined fixed frequency, the high voltage that can not obtain to expect, described fixed frequency are determined by the electrostatic capacitance in the design of inductance in the design of above-mentioned resonant inductor (Lh ') and above-mentioned resonant capacitor (Ch ').In addition, under situation about there are differences, the method that can consider to measure the resonance frequency of each lighting apparatus for discharge lamp and set each frequency, but, owing to need to consider in addition the influence of degree of closeness etc. of length, cable and other conductors of the cable that connected, therefore have the very difficult problem of setting resonance frequency in advance closely.

In order to address this problem, proposed in the past that driving frequency with converter (Ui ') is set at above-mentioned resonance frequency or near it or carry out the method for scanning motion.Figure 19 is the time diagram that simplifies a mode of ground expression lighting apparatus for discharge lamp in the past.(a) of this figure is illustrated in the waveform of the output voltage (Vnh) that produces in the above-mentioned resonant capacitor (Ch '), (b) represents the variation of the driving frequency (f) of above-mentioned converter (Ui).This is the mode of the frequency of lighting the alternating voltage that when beginning produce by converter (Ui ') being carried out automatic scan repeatedly in the prescribed limit of the resonance frequency that comprises resonant circuit, during in (Ta), begin to carry out scanning motion from lower frequency limit to upper limiting frequency, in consistent with the resonance frequency once in a while moment (ta) of the frequency of the alternating voltage that converter circuit produced, output voltage (Vnh) is a high voltage in this process.On the other hand, during in (Tb), begin to carry out backward scanning motion from upper limiting frequency to lower frequency limit.Therefore, in the scope of the specified time limit (T) when lighting beginning, in the scope of inferring the resonance frequency that according to above-mentioned difference, carry out repeatedly scanning motion repeatedly, can apply high voltage to discharge lamp (Ld).This high-tension crest voltage for example is set to 2kV～5kV.(voltage of above-mentioned crest voltage mensuration from 0V to the peak value obtains, and the method for measurement of the crest voltage of the ac high voltage in this specification is identical.)

Yet, start applying high voltage to discharge lamp above-mentioned during (T) during in, the driving frequency of converter (Ui ') depart from above-mentioned resonance frequency or near the frequency it during (during among the figure (Tc) representative, output voltage (Vnh) is lower whole during), the problem that exists voltage that output voltage (Vnh) can not take place to be caused by resonance fully to raise.

About the driving frequency timing consistent of the AC driving circuit of aforesaid uncertain converter etc., and, various technology had been proposed in the past at the whole scanning motion that during starts continues to carry out driving frequency repeatedly of discharge lamp with resonance frequency.

In Japanese kokai publication hei 02-215091 number, put down in writing following proposal: as produce the driving frequency condition consistent at least in a flash with resonance frequency, when lighting beginning, the frequency to the alternating voltage that converter circuit produced in the prescribed limit of the resonance frequency that comprises resonant circuit is carried out automatic scan.

In addition, in Japanese kokai publication hei 03-102798 number, put down in writing following proposal: apply the high-frequency unit that high voltage makes the lamp igniting in the lc circuit thereby comprise to lamp, this high-frequency unit is with the frequency of time to time change, and perhaps the frequency that begins to reduce in time from the frequency higher than resonance frequency applies high voltage to lc circuit.

In addition, in Japanese kokai publication hei 04-017296 number, put down in writing following proposal: when the frequency of oscillation with power converter cells is transformed to high-frequency, output voltage according to Sawtooth waves generation unit or triangular wave generation unit changes frequency of oscillation within the limits prescribed.

In addition, in Japanese kokai publication hei 04-272695 number, put down in writing following proposal: when starting, the control change device is so that the output frequency of converter begins continually varying scheme till the frequency below the frequency field that the resonance of the voice phenomenon can take place from the resonance frequency of Lc circuit, perhaps, when constant, control converter so that the output frequency of converter becomes the frequency below the frequency field that can produce the resonance of the voice phenomenon.

In addition, in Japanese kokai publication hei 10-284265 number, put down in writing following proposal: the scheme that in the scope of the resonance frequency that is during starts comprising resonant circuit, the frequency from the alternating voltage of output connecting portion output is scanned, perhaps, from the alternating voltage of output connecting portion output high frequency, during constant the lighting after the discharge lamp starting, only supply with the scheme of the interchange operation voltage of low frequency during starts to discharge lamp.

In addition, in TOHKEMY 2000-195692 number, the scanning of the operating frequency of carrying out the electric bridge in the resonance starting and the scheme that resonance point is passed through have been put down in writing as embodiment.

In addition, in TOHKEMY 2001-338789 number, put down in writing following proposal: make the switching frequency continually varying control of each switch element at the appointed time, the sweep limits of this switching frequency comprises the resonance frequency that is caused by the inductor of load resonant circuit and capacitor, and, during regulation, make frequency change the i.e. control of scanning from high to low, in addition, when resonance frequency changes after the discharge lamp insulation breakdown, the frequency of converter is also changed and provide big energy, make discharge lamp more stably transfer to arc discharge to arc discharge.

In addition, in TOHKEMY 2002-151286 number, put down in writing following proposal: the example of the scanning of the driving frequency of repeatedly carrying out converter is repeatedly arranged, also have the mode of lighting with electric arc from the example of high frequency to the low frequency transformation as embodiment.

In addition, in TOHKEMY 2004-146300 number, put down in writing following embodiment: the structure of having used 2 resonator systems, even the lower frequency limit of changeable frequency scope and upper limiting frequency be set at since the component differences of resonant circuit portion or from the high pressure discharge lamp lighting apparatus to the lamp between output line the electric capacity of floating influence and resonance frequency changes the variable range that also can cover (カ バ one), use microprocessor to carry out scanning motion.

In addition, in TOHKEMY 2004-221031 number, put down in writing following proposal: a kind of lighting apparatus for discharge lamp that possesses control unit, this control unit reduce above-mentioned square wave frequency stagely and to the frequency setting in the 1st stage of major general be resonant circuit resonance frequency the odd number branch 1 near, for the resonance potential that the difference that suppresses because of the LC parts produces, make the frequency and load (duty) change of the DC-DC translation circuit of the leading portion that is configured in converter.

In addition, in TOHKEMY 2005-038813 number, put down in writing following proposal as embodiment: in order to carry out odd number time resonance, the converter frequency of the HF switch action when making starting continuously or multistage ground change.

In addition, in TOHKEMY 2005-050661 number, put down in writing following proposal: when discharge lamp starts as embodiment, make the output frequency of converter begin to change continuously to lower limit from higher limit, and after arriving lower limit, turn back to higher limit once more and carry out identical action repeatedly, thereby pass through resonance point.

In addition, in TOHKEMY 2005-038814 number, put down in writing following proposal: utilize 2 switch elements to realize half-bridge function and buck chopper function as embodiment, in starting, for 1 frequency with the odd number branch of resonance frequency is moved, repeated segmentation also scans the frequency of converter.

In addition, in TOHKEMY 2008-243629 number, put down in writing following proposal: the scanning motion of implementing the frequency of converter in order to obtain resonance frequency repeatedly, perhaps, with the allocation of the converter of no-load condition, starting improvement pattern, constant illuminating state each pattern down be non-loaded＞constant＞start the improvement pattern.

So far, determine about the driving frequency timing consistent not with resonance frequency to the AC driving circuit of converter etc., and, the scheme of conventional art is illustrated at the whole scanning motion that during starts carries out driving frequency repeatedly constantly of discharge lamp.Yet, as mentioned above, make applying high voltage to discharge lamp (T) during its starting above-mentioned during in, converter (Ui ') to be to depart from above-mentioned resonance frequency or during frequency of frequency was moved near it, the rising of the voltage that is caused by resonance these the problems referred to above did not take place fully is not resolved.

In order to address this problem, following proposal had been proposed in the past: make the driving frequency automatic tuning of converter (Ui ') or be set at the above-mentioned resonance frequency of the resonant circuit that comprises above-mentioned resonant inductor (Lh ') and resonant capacitor (Ch ') or near it or the resonance frequency of high order.

Lighting apparatus for discharge lamp among above-mentioned Figure 18 is illustrated once more.In this circuit, possess and be used to make output voltage polarity inversion, the converter of full-bridge type (Ui '), resonant inductor (Lh ') and resonant capacitor (Ch '), carrying out polarity inversion with resonance frequency or near the frequency it drives, by consequent LC series resonance phenomenon, make between the two-terminal of above-mentioned resonant capacitor (C h ') and produce high output voltage (Vnh), (Ld) applies high voltage to above-mentioned discharge lamp, in order to control the voltage of above-mentioned output voltage (Vnh), be provided with as the tuning degree detecting unit (Un ') of having realized the detecting unit of resonance condition.

Figure 20 is the time diagram that simplifies a mode of ground expression lighting apparatus for discharge lamp in the past, and this figure is the situation about tuning degree detecting unit (Un '), and this tuning degree detecting unit (Un ') is used to control the converter relevant with series resonance (Ui ').(a) represent the waveform of the output voltage (Vnh) that produces in the above-mentioned resonant capacitor (Ch '), (b) represented the appearance of variation of the driving frequency (f) of above-mentioned converter (Ui ').This device carries out automatic scan in the frequency of lighting the alternating voltage that resonance frequency that beginning the time comprising resonant circuit produced converter (Ui ') in interior prescribed limit, during in (Td), begin to carry out scanning motion from lower frequency limit towards upper limiting frequency, in the moment (td), the tuning degree detecting unit (Un ') that is made of voltage detection unit detects has realized that resonance and output voltage (Vnh) have arrived target voltage, this frequency (fp) can be kept, continuous desired high voltage can be produced.

As mentioned above, crest voltage is 2kV～5kV because output voltage (Vnh) for example is set to, so tuning degree detecting unit (Un ') need have high voltage withstanding ability.As a mode of the detecting unit of having realized resonance condition, have between the tie point of mensuration resonant capacitor (Ch ') and resonant inductor (Lh ') and the ground connection or the voltage between the two ends of discharge lamp (Ld) and make the mode of its signalling.For example, for high voltage withstanding, a plurality of resistive elements of arranged in series, capacitor can be realized the intermediate point picked up signal from this dividing potential drop.But, under the situation of this mode,, therefore exist to be unfavorable for the miniaturization of lighting apparatus for discharge lamp, the problem of cost degradation because the number of component parts can increase.

In addition, other mode as the detecting unit of having realized resonance condition, following manner is arranged: to the additional secondary winding transformer of resonant inductor (Lh ') with suitable small turn number ratio, make resonant inductor (Lh ') become transformer device structure, use resistance, diode, capacitor etc. that the signal that obtains from above-mentioned secondary winding transformer, have roughly with the proportional amplitude voltage of amplitude voltage of above-mentioned resonant inductor (Lh ') is carried out rectification, thus with it as above-mentioned voltage detection unit.Yet, in this mode, owing in resonant inductor, produce above-mentioned high voltage during starting, therefore in resonant inductor (Lh ') as the transformer structure, need fully guarantee the insulation of secondary winding transformer with respect to the high voltage generating unit, therefore prevent insulation breakdown, corona discharge, adopted to possess sufficient insulating tape, the method for winding interlayer adhesive tape, separate the mode of each winding etc. by segmentation (section) that the result has produced the problem of cost increase.

Another kind of mode as the detecting unit of having realized resonance condition, in the time of can considering that resonance frequency at the driving frequency of converter (Ui ') and resonant circuit is consistent, utilization is flowed out the structure of the phenomenon of a plurality of electric currents from converter (Ui '), and is provided with the method for the current detecting unit of converter (Ui ').But, using under the situation of the resistance that for example resistance value is little as above-mentioned current detecting unit, owing in the constant action of discharge tube lighting, understand streaming current consistently, therefore can become the unnecessary resistance loss, the mode that perhaps current transformer (current transfomer) is configured in the output of converter (Ui ') can cause the problem of the increase of cost.

Another mode as the detecting unit of having realized resonance condition, the current phase detecting unit of converter and the voltage-phase detecting unit of converter have also been proposed to be provided with, and, be actually the scheme of feeding back with the phase relation that realizes regulation to the mode that detected converter current phase place and converter voltage phase place compare.But, in this mode, need to be used to carry out the circuit of relatively judging of phase place similarly, perhaps be used for the current transformer of current detecting, the resistance that current detecting is used, therefore the shortcoming that also exists cost to increase.

As mentioned above, have the detecting unit of having realized resonance condition about realizing, it is consistent with resonance frequency to be set at the driving frequency that makes converter, and produces continuous high-tension structure, has proposed various technology in the past.

For example, in Japanese kokai publication sho 52-121975 number, put down in writing following proposal: as the scanning motion frequency and when detecting condition of resonance the fixing device of operating frequency, the 3rd high order harmonic component driving transducer by resonance frequency, and converter is searched for resonance frequency, and moves with this frequency.

For example, in Japanese kokai publication sho 55-148393 number, put down in writing following proposal: as the structure of keeping resonance condition in self-oscillatory mode, when the starting of inflation discharge lamp, prepared to be used for to detect the unit of the electric current that resonant circuit flows and at rate of change for maximum or when maximum, by the voltage that is applied on the resonant circuit is carried out the change of current, can make converter keep the resonance frequency of resonant circuit.

In addition, in TOHKEMY 2000-012257 number, put down in writing following proposal: similarly, as the structure of keeping resonance condition in self-oscillatory mode, with resonance condition discharge at starting lamp the time, automatic tuning is carried out in the self-oscillation of the resonant circuit by inductor and capacitor.

In addition, put down in writing following proposal in Japanese Unexamined Patent Application Publication 2001-501767 number: have the state that is used for the detected gas discharge lamp and the detecting unit that constitutes, control circuit unit is as the function of the output of detecting unit and the structure of the frequency of control change device; Perhaps, have the effective feedback circuit unit that changes of the frequency that responds the electric power detecting unit and make converter, make near the structure the electric power that gaseous discharge lamp is supplied with maintains prescribed level; Perhaps, converter constitutes before gaseous discharge lamp starting and after the starting, utilization is carried out continuous action with the frequency that reduces near the mode of resonance frequency, converter also constitutes till the action of gaseous discharge lamp begins to be changed to arc mode from glow mode at least, utilization is moved with the frequency that the mode near near the frequency the characteristic frequency reduces, converter constitutes action at gaseous discharge lamp after glow mode is changed to arc mode, the high frequency of ratio resonance frequency with other is moved, gaseous discharge lamp is started thus, shifts and moves with steady state to arc mode from glow mode; Perhaps, can also have following step: before the gaseous discharge lamp starting, the frequency that utilization reduces in the mode near resonance frequency from characteristic frequency makes the step of converter action, gaseous discharge lamp from aura before the transfer of electric arc produces, the frequency that utilization increases towards near the of characteristic frequency makes the step of converter action, utilizes other the high frequency of resonance frequency that becomes the operating stably state than gaseous discharge lamp to make the step of converter action.

In addition, in Japanese Unexamined Patent Application Publication 2001-511297 number, put down in writing following proposal: proposed the detection mode relevant with determining method with the resonance frequency of the driving frequency of electric bridge, carry out the finding method of stochastical sampling, till the igniting of for example puncture of gas electric light (break down) and gaseous discharge lamp produces, carry out said method continuously.

In addition, in Japanese Unexamined Patent Application Publication 2001-515650 number, put down in writing following proposal: the electric bridge frequency is reduced, by controlling at first exciting the control of resonant ignitor ground than the sufficiently high frequency of nominal resonance frequency, on one side the repeater lamp terminal voltage reduce stimulating frequency on one side; Perhaps, if the terminal voltage of lamp increases to make frequency reduce then towards the nominal resonance frequency, reach the Min. value if measure the lamp terminal voltage in the frequency of being controlled, the then minimizing of controller stop frequency continues exciter lamp with this frequency in specifying minimum duration.

In addition, in TOHKEMY 2004-095334 number, put down in writing following proposal: in resonant circuit portion, be provided for detecting the driving voltage that converter drives frequency frequency detecting unit and be used to detect the voltage detection unit that drives the voltage that resonant circuit produced, make driving frequency from high-frequency to low frequency change, the frequency when voltage detection unit is reached maximum voltage is as driving frequency; Perhaps, make driving frequency from high-frequency to low frequency change, frequency when voltage detection unit is reached threshold voltage is as driving frequency, in addition, the detection of said frequencies is the structure that applies the constant voltage littler than the starting voltage that can make the discharge lamp starting to resonant circuit, and in addition, voltage detection unit is a structure of having utilized the secondary winding transformer of resonant inductor, perhaps, be the structure of measuring the tie point of resonant capacitor and resonant inductor.

In addition, in TOHKEMY 2004-127656 number, in order to light discharge lamp, by the frequency of having started the output voltage of converter circuit than the odd number time low frequency of resonance frequency of resonant circuit, then, the frequency of output voltage is risen or the rising of staged ground gradually, the frequency setting of the output voltage of converter circuit is become the frequency of the output voltage of setting when above for the amplitude in the vibration voltage of resonant circuit, perhaps, at the appointed time, under the amplitude of the output voltage of resonant circuit does not reach situation more than the setting, after the frequency of output voltage reaches higher limit, the speed that equates with the speed when improving frequency, frequency original frequency during with starting is a target, in the process that reduces frequency, if the amplitude of the output voltage of resonant circuit becomes more than the setting, then be set at frequency than low a few percent of frequency of this moment, on the other hand, in the process that reduces frequency, amplitude at the output voltage of resonant circuit does not become under the situation that has just reached original frequency more than the setting, improve the action of frequency repeatedly once more, till lighting or till having passed through predetermined maximum time.

In addition, in TOHKEMY 2004-327117 number, put down in writing following proposal: will be set in the operating frequency of the high frequency voltage that converter circuit portion produces near the frequency of the resonance frequency of resonant circuit or its odd-multiple, so that can export high-voltage pulse, and carry out frequency scanning so that can export the high-voltage pulse of almost fixed, detect resonance step-up voltage, the moment of target voltage values stops resonance step-up voltage becoming roughly, and perhaps fixedly operating frequency is exported continuously with target voltage values roughly during certain; Perhaps, to scanning direction so far and contrary direction operating frequency is scanned the roughly output continuously below the target voltage values during certain in the moment that becomes target voltage values roughly; Perhaps, the resonance potential detecting unit is made of the secondary winding of the inductance of resonant circuit; Perhaps, the resonance potential detecting unit is made of the divider resistance that is connected with the two ends of the capacitor of resonant circuit; Perhaps, carry out the control of frequency scanning by microprocessor.

In addition, put down in writing following proposal at Japanese Unexamined Patent Application Publication 2005-520294 number: in order to carry out automatic tuning, tuning about based on the automatic feedback of 3 resonance, for example, the test section of the high voltage output that produces as resonant circuit and use antenna circuit and use the PLL circuit to feed back.

In addition, in Japanese Unexamined Patent Application Publication 2005-515589 number, put down in writing following proposal: carry out having used the feedback of VCO and microprocessor, feedback voltage, electric current, high voltage as carrying out the structure of automatic tuning.

In addition, put down in writing a kind of ballast (ballast) equipment in Japanese Unexamined Patent Application Publication 2005-507554 number: the value and the time fluctuation switching frequency of the coefficient of self-inductance of winding (coil) and the electrostatic capacitance of capacitor are determined interrelatedly, so that the high order harmonic component frequency that the some time during frequency variation engraves the odd number time of stating the time fluctuation switching frequency is at least near the resonance frequency of winding and capacitor.

In addition, put down in writing following proposal at Japanese Unexamined Patent Application Publication 2005-507553 number: carry out the higher order resonances action in order to make the electric bridge in the igniter action, be provided for measuring the unit of the both end voltage of discharge lamp, before discharge beginning, the driving frequency that is used to carry out the electric bridge that resonance moves is scanned, when reaching target voltage, make the structure of fixed-frequency, and lighting the method that after-stage ground changes the low frequency action into.

In addition, put down in writing following proposal in TOHKEMY 2007-103290 number: be provided for measuring the unit of the voltage that produces in the resonant circuit, the frequency of the electric bridge of resonance action, fixed frequency when reaching target voltage are carried out in scanning when non-loaded.

In addition, in TOHKEMY 2007-173121 number, put down in writing following proposal: the driving frequency of converter is begun to low frequency change or interim change continuously from high-frequency, based on the value that obtains from resonance potential, judge whether resonance potential has reached the 2nd level, after having obtained to reach the judged result of the 2nd level, make variable fixed-frequency so that resonance potential is maintained the 2nd level.

In addition, in TOHKEMY 2007-179869 number, put down in writing following proposal: on one side the frequency control circuit in the starting sequence of discharge lamp monitors the tuning degree signal, make the scanning motion of frequency control signal variation on one side, beginning in the scope that is no more than another frequency, to scan from the upper limiting frequency of vairable-frequency oscillator or a frequency the lower frequency limit, frequency control circuit is after scanning motion finishes, determine for the value of the frequency control signal of the resonance frequency of resonant circuit and with its incoming frequency variable oscillator, in addition, for corresponding with the deviation (drift) of resonance frequency, after the value of having determined frequency control signal, proceed scanning motion across close limit, in addition, be to use the formation of resonant circuit arranged side by side at resonant circuit, thereby resonant inductor can have been monitored the tuning degree signal as transformer structure structure.

In addition, in TOHKEMY 2008-027705 number, put down in writing following proposal: constitute the secondary winding transformer that makes resonant inductor as first voltage measuring unit for measuring and be connected with resistance, thereby be used in the feedback of the high voltage output that causes by resonance effect with capacitor.

In addition, in TOHKEMY 2008-269836 number, put down in writing following proposal: in order to be used in the feedback of the high voltage output that causes by resonance effect, constituting the secondary winding transformer that makes resonant inductor is connected with resistance with capacitor, detect resonance potential indirectly, the converter driving frequency is fixed as frequency when reaching target voltage.

So far, consistent about having the detecting unit of having realized resonance condition, be set at the driving frequency that makes converter with resonance frequency, realize producing continuous high-tension structure, be illustrated with reference to the scheme of conventional art.Yet, as mentioned above,, therefore have the problem of cost increase owing to need realize the detecting unit of resonance condition.

Above-described problem is, is accompanied by resonance phenomena and produces high voltage and apply this high voltage to lamp in resonant circuit, thereby have the problem that the step of insulation breakdown takes place in the lamp that makes.But, realize stablizing illuminating state in order to make lighting apparatus for discharge lamp, existing must be safe and finish the problem of following step reliably, this step is that insulation breakdown takes place in the lamp, after the discharge beginning, the driving frequency that makes converter again is from the step of high resonance frequency to the low frequency transformation of final stable illuminating state.

As technology, can enumerate: the technology that in this process, comprises the function of the resonance starting that changes reliably to arc discharge from glow discharge in the driving frequency of switching converter when discharge lamp applies high voltage and when stable; Perhaps, in this process, comprised making only bringing together at short notice of being occurred in the start mode that applies high frequency, and when suppressing electrode damaged, stably changed the technology etc. of the function of lighting on two directions at electrode for discharge lamp into to the asymmetric electric discharge phenomena of a side direction streaming current of electrode for discharge lamp.

In order to improve such scheme, proposed to switch or change effectively the method for the frequency of converter, perhaps the method for the current value of changing flow direction discharge lamp in the past.

In Japanese kokai publication hei 03-167795 number, put down in writing following proposal: when the discharge that detects discharge lamp begins, the frequency of the operating frequency that makes switch element when non-loaded changes the frequency when lighting into and when becoming asymmetric discharge gradually, owing to do not reduce frequency sharp, therefore can prevent to the mobile extreme overcurrent of the direction of lighting.

In addition, in Japanese kokai publication hei 04-121997 number, put down in writing following proposal: lamp starting back from resonance frequency or should near frequency begin perhaps to reduce frequency continuously to the low frequency switching.

In addition, in Japanese kokai publication hei 04-342990 number, put down in writing following proposal: when discharge lamp starts, it with the output frequency near the state-driven converter of the frequency the resonance frequency of LC series resonant circuit, if the output of lamp current detecting unit surpasses setting, the output of converter or frequency are switched to predetermined value after the minimizing.

In addition, in Japanese kokai publication hei 07-169583 number, put down in writing following proposal: the frequency control unit that the frequency change of the output voltage that makes the DC-AC translation circuit is set, when lighting judgment unit judges and go out discharge lamp and be non-illuminating state, frequency control unit is increased to the frequency of the output voltage of DC-AC converter unit the value of the series resonance that is enough to cause inductor and capacitor, in addition, when lighting judgment unit judges and go out discharge lamp and be illuminating state, frequency control unit reduces the frequency of the output voltage of DC-AC translation circuit.

In addition, in Japanese kokai publication hei 07-230882 number, put down in writing following proposal: the specified time limit after starting, by more than the resonance frequency of series resonant circuit and near the frequency the resonance frequency make the continuous action of converter portion.

In addition, in Japanese kokai publication hei 08-124687 number, put down in writing following proposal: have the frequency control switching circuit, this frequency control switching circuit only makes the full-bridge action with the higher order resonances frequency when resonant circuit is non-loaded, apply low-frequency voltage to lamp after lighting.

In addition, in Japanese kokai publication hei 11-265796 number, put down in writing following proposal: when judging discharge lamp and changed illuminating state into and judge, frequency is switched to predetermined value after the minimizing.

In addition, in TOHKEMY 2004-265707, put down in writing following proposal: use the LC resonant circuit to make the action of full-bridge higher order resonances frequency, apply low-frequency voltage to lamp lighting the back, resonant circuit make produce high-tension during with output dc voltage during or different during alternately repeat.

In addition, in TOHKEMY 2008-171742, put down in writing following proposal: beginning through after the stipulated time from the lamp starting, judgement is root discharge or front end discharge, switches to the constant action of low frequency from the high frequency action under the situation of front end discharge, continues the high frequency action under the situation of root discharge.

In addition, in TOHKEMY 2007-005260, put down in writing following proposal: have the switching part that switches in the electric current that flows between two electrodes, if being used to judge discharge lamp is that the all-wave discharge or the decision circuitry of asymmetric discharge are judged as the all-wave discharge, then supply with the constant current that sets so that discharge lamp is lighted state-transition to stablizing in specified time limit to discharge lamp, on the other hand, if decision circuitry is judged as half-wave discharge, then supply with the big electric current of the above-mentioned constant current of peakedness ratio to discharge lamp DL.

The prior art document

Patent documentation

Patent documentation 1: Japanese kokai publication hei 02-215091 number

Patent documentation 2: Japanese kokai publication hei 03-102798 number

Patent documentation 3: Japanese kokai publication hei 04-017296 number

Patent documentation 4: Japanese kokai publication hei 04-272695 number

Patent documentation 5: Japanese kokai publication hei 10-284265 number

Patent documentation 6: TOHKEMY 2000-195692 number

Patent documentation 7: TOHKEMY 2001-338789 number

Patent documentation 8: TOHKEMY 2002-151286 number

Patent documentation 9: TOHKEMY 2004-146300 number

Patent documentation 10: TOHKEMY 2004-221031 number

Patent documentation 11: TOHKEMY 2005-038813 number

Patent documentation 12: TOHKEMY 2005-050661 number

Patent documentation 13: TOHKEMY 2005-038814 number

Patent documentation 14: TOHKEMY 2008-243629 number

Patent documentation 15: Japanese kokai publication sho 52-121975 number

Patent documentation 16: Japanese kokai publication sho 55-148393 number

Patent documentation 17: TOHKEMY 2000-012257 number

Patent documentation 18: Japanese Unexamined Patent Application Publication 2001-501767 number

Patent documentation 19: Japanese Unexamined Patent Application Publication 2001-511297 number

Patent documentation 20: Japanese Unexamined Patent Application Publication 2001-515650 number

Patent documentation 21: TOHKEMY 2004-095334 number

Patent documentation 22: TOHKEMY 2004-127656 number

Patent documentation 23: TOHKEMY 2004-327117 number

Patent documentation 24: Japanese Unexamined Patent Application Publication 2005-520294 number

Patent documentation 25: Japanese Unexamined Patent Application Publication 2005-515589 number

Patent documentation 26: Japanese Unexamined Patent Application Publication 2005-507554 number

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Make the driving frequency of converter (Ui ') consistent for having the detecting unit of having realized resonance condition, being set at,, have the problem that can not solve by conventional art to realize producing continuous high-tension structure with resonance frequency.Formation about the detecting unit of having realized resonance condition, any following situation all can cause the increase of cost: as mentioned above, for high voltage withstanding, a plurality of resistive elements, capacitors in series are being arranged, and from the mode of dividing point picked up signal, the number of component parts increases; Perhaps, go up in the mode of adding secondary winding transformer, need fully guarantee the insulation of secondary winding transformer with respect to the high voltage generating unit with small turn number ratio at resonant inductor (Lh '); Perhaps, do not detect in the mode of resonance current, current transformer need be set not using resistance; Perhaps, detect in the mode of condition of resonance, need be provided for carrying out the circuit of relatively judging of phase place in phase place by voltage and current.

In addition, for high-intensity discharge lamp, if not the state that lamp does not discharge then is difficult to judge whether to have realized resonance condition.This be because, in glow discharge or arc discharge generating process, as Zener diode, the voltage of lamp two interpolars become lamp discharge condition intrinsic voltage, and because lamp consumes power consumption, the Q value of resonant circuit becomes low-down state.

For example, detecting voltage and becoming under the situation of the highest condition to find out while detecting the scanning motion that the voltage that lamp is applied carries out the driving frequency of converter (Ui '), if realize then lantern festival generation discharge of resonance condition, detect voltage on the contrary and reduce, therefore exist to be difficult to judge the problem that voltage becomes the highest condition that detects of finding out.In addition, even supposed to carry out to judge that the High Level of sequence is so that produce the realization that discharge also can detect resonance condition, but because the electric discharge phenomena that take place under the scanning motion of frequency have resume, that original corresponding relation should be is man-to-man, covered based on the relation between the driving frequency of the rise of the voltage of resonance phenomena and converter, so is difficult to find out the optimum value of the driving frequency of converter (Ui ').

In addition, also must finish the driving frequency that makes converter safely and reliably and begin the step that the low frequency to final stable illuminating state changes from high resonance frequency.Even to glow discharge or arc discharge state-transition, till the discharging substance of being enclosed in lamp was gasified totally, the possibility that discharge is interrupted taking place existed always.For example under the situation of the high-pressure mercury-vapor lamp of having enclosed mercury, the arc discharge that is called as field emission from the accompanying liquid water silver hair life of the electrode of negative electrode, if liquid mercury exhausts, then be back to glow discharge, but because glow discharge is than arc-over voltage height, the possibility that exists discharge to interrupt can not be provided under the voltage condition of enough keeping glow discharge at once at power supply circuits.In order to make the probability of happening vanishing of this phenomenon, the someone has expected improving the method for the ability of power supply circuits, and this generally causes cost to increase thereby be unrealistic, therefore, when discharge is interrupted taking place, the formation that needs to begin once more at once the resonance starting.

In addition, insulation breakdown takes place in the lamp even make by resonance starting, discharge begins successfully, but the flow direction for the electric current of two directions of high-frequency ac, if can not finish the transformation from glow discharge to the arc discharge at short notice, then the time of origin of the sputter phenomenon of the electrode of discharge lamp is elongated, makes electrode degradation, cause the alienation of the quartz of lamp inner face, the result has the danger that causes the life-span variation.Particularly, do not change arc discharge in the discharge to the flow direction of the electric current of a side, under the situation about continuing between so-called asymmetric discharge is long-term, for example continue after low frequency changes always, this has bad influence to the above-mentioned lamp life-span.

Summary of the invention

Problem to be solved by this invention provides a kind of elimination that can promote the state of asymmetric discharge, the lighting apparatus for discharge lamp of the property lighted reliably of discharge lamp in the time of can guaranteeing to start.

The lighting apparatus for discharge lamp of technical scheme 1 of the present invention, be used to light discharge lamp (Ld), in this discharge lamp (Ld) arranged opposite a pair of electrode (E1, E2) that is used for main discharge, this lighting apparatus for discharge lamp is characterised in that, have: power supply circuits (Ux), (Ld) powers to above-mentioned discharge lamp; Power-supplying circuit (Fx) is used to control above-mentioned power supply circuits (Ux); Converter (Ui) is arranged on the back level of above-mentioned power supply circuits (Ux), makes the polarity of voltage counter-rotating that above-mentioned discharge lamp (Ld) is applied; Cycle drive circuit (Uj) generates converter drive signal (Sj), and this converter drive signal (Sj) is to be used for the cyclical signal that the cycle drives above-mentioned converter (Ui); And resonant circuit (Nh), be arranged on the back level of above-mentioned converter (Ui), comprise resonant inductor (Lh) and resonant capacitor (Ch), be used for when above-mentioned discharge lamp (Ld) starts improving service voltage to above-mentioned discharge lamp (Ld) by the boosting that is accompanied by resonance phenomena, in the starting sequence of above-mentioned discharge lamp (Ld), above-mentioned cycle drive circuit (Uj) generates the corresponding converter drive signal of resonance frequency (Sj) with above-mentioned resonant circuit (Nh), and above-mentioned power-supplying circuit (Fx) is controlled, even so that begin to be accompanied by under the situation that the boosting of the resonance phenomena in the above-mentioned resonant circuit (Nh) disappears in discharge owing to above-mentioned discharge lamp (Ld), the voltage that also makes above-mentioned power supply circuits (Ux) output be enough to keep the discharge of above-mentioned discharge lamp (Ld) is non-loaded open voltage (Vop), then, above-mentioned cycle drive circuit (Uj) generates above-mentioned converter drive signal (Sj), so that the frequency of above-mentioned converter (Ui) begins to descend gradually till reaching the 1st thresfhold frequency (fj1) from the frequency corresponding with the resonance frequency of above-mentioned resonant circuit (Nh), if the frequency of above-mentioned converter (Ui) reaches above-mentioned the 1st thresfhold frequency (fj1), then above-mentioned cycle drive circuit (Uj) generates above-mentioned converter drive signal (Sj), so that the frequency of above-mentioned converter (Ui) becomes stable ignition frequency (fstb), and above-mentioned power-supplying circuit (Fx) controls so that above-mentioned power supply circuits (Ux) output is enough to keep the electric current of the discharge of above-mentioned discharge lamp (Ld).

The lighting apparatus for discharge lamp of technical scheme 2 of the present invention, as technical scheme 1 described lighting apparatus for discharge lamp, it is characterized in that, if the frequency of above-mentioned converter (Ui) reaches above-mentioned the 1st thresfhold frequency (fj1), then above-mentioned cycle drive circuit (Uj) inserts following actions in generation above-mentioned converter drive signal (Sj) before so that the frequency of above-mentioned converter (Ui) becomes stable ignition frequency (fstb), promptly, generate above-mentioned converter drive signal (Sj) so that the frequency of above-mentioned converter (Ui) becomes 2nd thresfhold frequency (fj2) lower than above-mentioned the 1st thresfhold frequency (fj1), generate above-mentioned converter drive signal (Sj) then so that the frequency of above-mentioned converter (Ui) drops to aforementioned stable ignition frequency (fstb) gradually.

The lighting apparatus for discharge lamp of technical scheme 3 of the present invention, as technical scheme 1 or 2 described lighting apparatus for discharge lamp, it is characterized in that, with undertaken by above-mentioned cycle drive circuit (Uj), generate above-mentioned converter drive signal (Sj) so that the frequency of above-mentioned converter (Ui) begins till reaching the 1st thresfhold frequency (fj1) action that descends gradually concurrently from the frequency corresponding with the resonance frequency of above-mentioned resonant circuit (Nh), above-mentioned power-supplying circuit (Fx) is controlled, so that the voltage that above-mentioned power supply circuits (Ux) output descends gradually, till the voltage (Vo2) that reaches the regulation lower than above-mentioned non-loaded open voltage (Vop).

The invention effect

By being suitable for the present invention, can provide a kind of elimination that can promote the state of asymmetric discharge, the lighting apparatus for discharge lamp of the property lighted reliably of discharge lamp in the time of can guaranteeing to start.

Description of drawings

Fig. 1 is the block diagram of a mode that simplifies the embodiment of ground expression lighting apparatus for discharge lamp of the present invention.

Fig. 2 is the block diagram of a part～individual mode of the embodiment of abstract ground expression lighting apparatus for discharge lamp of the present invention.

Fig. 3 represents the formation of a mode of a part of the embodiment of lighting apparatus for discharge lamp of the present invention with simplifying.

Fig. 4 represents the formation of a mode of a part of the embodiment of lighting apparatus for discharge lamp of the present invention with simplifying.

Fig. 5 is the schematic diagram of waveform of a mode of the embodiment of expression lighting apparatus for discharge lamp of the present invention.

Fig. 6 is the schematic diagram of characteristic of a mode of the embodiment of expression lighting apparatus for discharge lamp of the present invention.

Fig. 7 is the time diagram of a mode that simplifies the embodiment of ground expression lighting apparatus for discharge lamp of the present invention.

Fig. 8 is the time diagram of a mode that simplifies the embodiment of ground expression lighting apparatus for discharge lamp of the present invention.

Fig. 9 is the time diagram of a mode that simplifies the embodiment of ground expression lighting apparatus for discharge lamp of the present invention.

Figure 10 is the flow chart of a mode that simplifies the embodiment of ground expression lighting apparatus for discharge lamp of the present invention.

Figure 11 is the block diagram of a mode that simplifies the embodiment of ground expression lighting apparatus for discharge lamp of the present invention.

Figure 12 is the block diagram of a mode that simplifies the embodiment of ground expression lighting apparatus for discharge lamp of the present invention.

Figure 13 is the time diagram that simplifies a mode of ground expression lighting apparatus for discharge lamp of the present invention.

Figure 14 is the time diagram of a mode that simplifies the embodiment of ground expression lighting apparatus for discharge lamp of the present invention.

Figure 15 is the measured drawing of waveform of a mode of the embodiment of expression lighting apparatus for discharge lamp of the present invention.

Figure 16 is the time diagram of a mode that simplifies the embodiment of ground expression lighting apparatus for discharge lamp of the present invention.

Figure 17 is the time diagram of a mode that simplifies the embodiment of ground expression lighting apparatus for discharge lamp of the present invention.

Figure 18 represents the formation of a mode of lighting apparatus for discharge lamp in the past with simplifying.

Figure 19 is the time diagram that simplifies a mode of ground expression lighting apparatus for discharge lamp in the past.

Figure 20 is the time diagram that simplifies a mode of ground expression lighting apparatus for discharge lamp in the past.

Description of reference numerals

3 about 100kHz of resonance

The B10 processing block

The B12 processing block

The B13 processing block

The B14 processing block

The B15 processing block

The B16 processing block

The B21 processing block

The B23 processing block

The B24 processing block

The Ch resonant capacitor

Ch ' resonant capacitor

The Cpt capacitor

The Cx smmothing capacitor

DSf frequency control signal variable

The Dr diode

Dsf frequency control signal variable

DsfOptim FREQUENCY CONTROL optimum value variable

Dsn tuning degree signal variable

The minimum tuning degree signal variable of DsnMin

Dx inertia diode

The E1 electrode

The E2 electrode

The Ex lighting apparatus for discharge lamp

F_Valid detects end mark

The Fx power-supplying circuit

The G1 gate driver circuit

The G2 gate driver circuit

The G3 gate driver circuit

The G4 gate driver circuit

The Gx gate driver circuit

The IL lamp current

Ih saturation limit current value

Ix supply current detecting unit

The Ld discharge lamp

The Lh resonant inductor

Lh ' resonant inductor

The Lx choking-winding

The Mx DC power supply

The Nh resonant circuit

The Q1 switch element

The Q2 switch element

The Q3 switch element

The Q4 switch element

The Qx switch element

Rr resistance

The Sf frequency control signal

Sf1 convertor controls signal

Sf2 convertor controls signal

Sfmax upper limiting frequency respective value

Sfmin lower frequency limit respective value

The Sg gate drive signal

Si supply current detection signal

Sj converter drive signal

Sn tuning degree signal

The Snmin minimum value

Sv supply power voltage detection signal

During the T

The T01 node

The T02 node

The T11 node

The T12 node

The T21 node

The T22 node

The T31 node

The T32 node

The T41 node

The T42 node

During the Ta

During the Tb

During the Tc

During the Td

During the Ti

During the Tm

During the Tm '

During the Tn

During the Tp

During the Tq

The Uc inverter drive circuit

The Uf frequency control circuit

The Ui converter

Ui ' converter

Uj cycle drive circuit

Un tuning degree detecting unit

Un ' tuning degree detecting unit

The Up constant voltage source

The Ux power supply circuits

Ux ' power supply circuits

Power circuit during Uy scanning

Vcc control circuit DC power supply

The Vnh output voltage

Vo2 voltage

Vop is non-loaded open voltage

Vx supply power voltage detecting unit

The Z load

The f frequency

F0 first-harmonic resonance frequency

F0/33 resonance frequency

F0/55 resonance frequency

Fj1 first thresfhold frequency

Fj2 second thresfhold frequency

The fp frequency

Fstb stablizes ignition frequency

Ta constantly

Tc constantly

Td constantly

Th constantly

Ti constantly

Tj constantly

Tn constantly

Tr constantly

Ts constantly

Tt constantly

Tu constantly

Tv constantly

Tw constantly

Tz constantly

Embodiment

At first, use the block diagram of the mode of the embodiment that has represented lighting apparatus for discharge lamp of the present invention is that Fig. 1 describes with simplifying.The power supply circuits (Ux) that are made of switching circuit of modes such as buck chopper, boost chopper etc. are according to the state of discharge lamp (Ld) or light sequence (sequence) and export suitable voltage and current.The converter (Ui) that is made of full-bridge circuit etc. is transformed to for example alternating voltage and the output of periodic inversion with the output voltage of above-mentioned power supply circuits (Ux), applies voltage via the resonant circuit (Nh) that comprises resonant inductor (Lh) and resonant capacitor (Ch) to a pair of electrode (E1, E2) that is used for main discharge of above-mentioned discharge lamp (Ld).

In addition, the non-loaded open voltage that applies when lamp starts is typically roughly about 200V, modulating voltage during glow discharge is typically 100V～200V, just having become arc discharge modulating voltage afterwards is typically about 10V, above-mentioned power supply circuits (Ux) are controlled as mobile electric current and are no more than the predetermined restricted current value when glow discharge and during arc discharge.

The resonance frequency of above-mentioned resonant circuit (Nh) mainly depends on the electrostatic capacitance of above-mentioned resonant capacitor (Ch) and the amassing of inductance of above-mentioned resonant inductor (Lh) calculated.When starting, to the periodic converter drive signal (Sj) of above-mentioned converter (Ui) output from cycle drive circuit (Uj).For above-mentioned converter drive signal (Sj) from above-mentioned cycle drive circuit (Uj), when above-mentioned resonance frequency becomes the relation of first-harmonic resonance or higher order resonances or approaching with it relation, in above-mentioned resonant circuit (Nh), produce resonance phenomena and flow through resonance current, in above-mentioned resonant inductor (Lh) and above-mentioned resonant capacitor (Ch), produce high voltage.

For example, node (T31) is 200V with respect to the voltage of node (T32), and between node (T42) and node (T41), the above-mentioned electrode that the main discharge of promptly above-mentioned discharge lamp (Ld) is used (E1, E2) applies crest voltage 2kV～5kV.

Owing to there is the difference of above-mentioned resonant circuit (Nh), specifically, the difference of the resonance frequency that existence causes because of the difference of inductance of the electrostatic capacitance of above-mentioned resonant capacitor (Ch), above-mentioned resonant inductor (Lh) etc., therefore, set up in order to make condition of resonance, in the present invention, can change the driving frequency of above-mentioned converter (Ui).Therefore, generate the above-mentioned cycle drive circuit (Uj) of the above-mentioned converter drive signal (Sj) be used to drive above-mentioned converter (Ui), comprising the variable oscillator of frequency of oscillation as inscape is vairable-frequency oscillator.Above-mentioned cycle drive circuit (Uj) is the input of receive frequency control signal (Sf) and the circuit of control frequency of oscillation, can use that to close between the frequency height of the pressure height of voltage of this frequency control signal (Sf) and frequency of oscillation be for example positively related circuit.Can certainly use the circuit of negative correlation.

On the other hand, for the frequency of oscillation and the resonance frequency that make above-mentioned cycle drive circuit (Uj) tuning, need to detect condition of resonance and set up which kind of degree, therefore, must to constitute the resonance frequency that can generate size and the frequency of above-mentioned converter (Ui) and above-mentioned resonant circuit (Nh) be the above-mentioned tuning degree signal (Sn) that the difference of basic rate or this higher order resonances frequency changes accordingly to tuning degree detecting unit (Un).In order to realize this result, the above-mentioned constant voltage source (Up) of power circuit (Uy) when constituting scanning can independently be set, owing to possess control circuit DC power supply (Vcc) in the lighting apparatus for discharge lamp, this control circuit makes the control circuit action of sequence control, logical circuit, analog etc. with DC power supply (Vcc), in Fig. 1, represented above-mentioned control circuit is also used as with DC power supply (Vcc) situation of above-mentioned constant voltage source (Up).In addition, above-mentioned control circuit generally uses the voltage of 3.3V～20V with DC power supply (Vcc).In addition, above-mentioned control circuit also can be the power supply of supplying with from the outside with DC power supply (Vcc).The circuit of this figure constitutes, at above-mentioned power supply circuits (Ux) when being in halted state, via the series circuit of resistance (Rr) and diode (Dr), from above-mentioned control circuit node (T21) service voltage of DC power supply (Vcc) to the input side of the positive electrode of converter (Ui).And, obtain above-mentioned tuning degree signal (Sn) from the tie point of above-mentioned diode (Dr) and above-mentioned resistance (Rr).

Above-mentioned control circuit is 3.3V～20V with DC power supply (Vcc), therewith relatively, just becoming under the state of the highest non-loaded open voltage at output voltage, the output of above-mentioned power supply circuits (Ux) becomes roughly about 200V, above-mentioned diode (Dr) is set so that do not apply high voltage from above-mentioned power supply circuits (Ux) to above-mentioned control circuit with DC power supply (Vcc).

Fig. 2 is the block diagram of a mode of a part of the embodiment of abstract ground expression lighting apparatus for discharge lamp of the present invention, and wherein the above-mentioned constant voltage source (Up) during for halted state and the load-side of this power supply illustrate as equivalent electric circuit with the above-mentioned power supply circuits (Ux) of above-mentioned Fig. 1 record.Like this, above-mentioned converter (Ui), resonant inductor (Lh) and resonant capacitor (Ch) can be handled as 1 load (Z).In addition, because above-mentioned discharge lamp (Ld) is the non-state of lighting, therefore be not included in the above-mentioned load (Z).

Make electric current flow to above-mentioned load (Z) via above-mentioned resistance (Rr) and above-mentioned diode (Dr) from above-mentioned constant voltage source (Up), and, monitor the mid point that is connected in series of above-mentioned resistance (Rr) and above-mentioned diode (Dr), and with this current potential as above-mentioned tuning degree signal (Sn).In the power consumption of above-mentioned load (Z) hour, the electric current that flows out from above-mentioned constant voltage source (Up) is little, thereby little in the voltage decline of above-mentioned resistance (Rr), therefore the current potential of above-mentioned tuning degree signal (Sn) is expressed as the high voltage near the output voltage of above-mentioned constant voltage source (Up).On the contrary, when the power consumption of above-mentioned load (Z) was big, the electric current that flows out from above-mentioned constant voltage source (Up) was big, thereby it is big to descend at the voltage of above-mentioned resistance (Rr), and therefore above-mentioned tuning degree signal (Sn) becomes the electronegative potential approaching with earthing potential.

At this, the frequency to the above-mentioned converter (Ui) that constitutes above-mentioned load (Z) in comprising the scope of resonance frequency is implemented scanning motion.At this moment, the electric power that on state resistance consumed that constitutes the switch element for example described later (Q1, Q2, Q3, Q4) of above-mentioned converter (Ui) increases along with the increase of the electric current that flows through element, the driving frequency of above-mentioned converter (Ui) is more near resonance frequency, the consumption electric power of above-mentioned load (Z) is big more, and the current potential of above-mentioned tuning degree signal (Sn) is low more.

In this case, power circuit (Uy) during as the above-mentioned scanning of carrying out the certain power supply of supply capacity, used the certain current-limiting resistance that utilizes above-mentioned resistance (Rr) to limit so that supply capacity becomes certain structure, power circuit during as above-mentioned scanning (Uy), also can be other for example make the certain or supply capability certain structure of supply current by restriction.In addition, not only being defined as certain structure on the direct current, also can be the certain current impulse row of mean value, power pulse row.Wherein, " necessarily " described herein, it is tight certain not to be meant that whole sweep limits at the driving frequency of above-mentioned converter (Ui) all requires, and roughly necessarily gets final product in the scope near resonance frequency at least.Otherwise the current potential of the input side by finding out above-mentioned converter (Ui) is minimum condition, and tuning the reaching that can detect to resonance frequency gets final product.Like this under the certain condition of power supply of little supply capacity, power to above-mentioned converter (Ui), make the drive frequency variations of above-mentioned converter (Ui) while the current potential of the input side that monitors above-mentioned converter (Ui), thereby can correctly know the condition that resonance condition realizes.

In addition, about concrete little which kind of degree that arrives in the certain condition of power supply of above-mentioned little supply capacity, even importantly want little under situation about having realized,, the degree of insulation breakdown can not take place in the above-mentioned discharge lamp (Ld) that is connected based on the resonance potential that is produced in resonance condition.This be because, as mentioned above, if insulation breakdown takes place in the above-mentioned discharge lamp (Ld), the current potential of the input side of the above-mentioned converter (Ui) that is then monitoring can irregular variation, thereby is difficult to the condition of knowing that correctly resonance condition realizes.

Fig. 3 is an example of specializing of the expression above-mentioned power supply circuits (Ux) that can use in lighting apparatus for discharge lamp of the present invention.Buck circuit is accepted voltage for the above-mentioned power supply circuits (Ux) on basis from the DC power supply (Mx) of PFC etc. and is supplied with and move, and carries out the amount of power supply adjustment to above-mentioned discharge lamp (Ld).In above-mentioned power supply circuits (Ux), switch element (Qx) by FET etc. makes current lead-through (ON) from above-mentioned DC power supply (Mx), disconnects (OFF), via choking-winding (Lx) smmothing capacitor (Cx) is charged, (Ld) applies this voltage to above-mentioned discharge lamp, and electric current can flow to above-mentioned discharge lamp (Ld).

In addition, during above-mentioned switch element (Qx) conducting state, utilize electric current by above-mentioned switch element (Qx), directly carry out to the charging of above-mentioned smmothing capacitor (Cx) with to electric current supply as the above-mentioned discharge lamp (Ld) of load, and in choking-winding (Lx) with the form energy accumulation of magnetic flux, during above-mentioned switch element (Qx) off-state, the energy that utilization is accumulated with the form of magnetic flux in above-mentioned choking-winding (Lx) carries out to the charging of above-mentioned smmothing capacitor (Cx) with to the electric current supply of above-mentioned discharge lamp (Ld) via inertia diode (Dx).In addition, be meant that above-mentioned switch element (Qx) is in off-state and the state that stops with reference to the halted state of the above-mentioned power supply circuits (Ux) among the illustrated Fig. 1 of Fig. 2 before.

In the above-mentioned power supply circuits (Ux) of above-mentioned buck chopper type, the ratio with action cycle of above-mentioned switch element (Qx) during the conducting state by above-mentioned switch element (Qx) is the load cycle ratio, can adjust the amount of power supply to above-mentioned discharge lamp.At this, generate gate drive signal (Sg) with certain load cycle ratio by power-supplying circuit (Fx), control the gate terminal of above-mentioned switch element (Qx) via gate driver circuit (Gx), control conducting, disconnection thus from the electric current of above-mentioned DC power supply (Mx).

Constitute and to detect lamp current that is flow through between electrode (E1, E2) and the modulating voltage that between electrode (E1, E2), produces by supply current detecting unit (Ix) and supply power voltage detecting unit (Vx) at above-mentioned discharge lamp (Ld).In addition, can use shunt resistance to realize above-mentioned supply current detecting unit (Ix) simply, can also use divider resistance to realize above-mentioned supply power voltage detecting unit (Vx) simply.

Be transfused to above-mentioned power-supplying circuit (Fx) from the supply current detection signal (Si) of above-mentioned supply current detecting unit (Ix) and from the supply power voltage detection signal (Sv) of above-mentioned supply power voltage detecting unit (Vx).Above-mentioned power-supplying circuit (Fx) feedback ground generates above-mentioned gate drive signal (Sg), so as when lamp to start do not flow through lamp current during, non-loadedly to open voltage and export the voltage of regulation in order to apply to lamp.In addition, above-mentioned power-supplying circuit (Fx) flows through under the situation of discharging current in the lamp starting, and feedback ground generates above-mentioned gate drive signal (Sg) so that the export target lamp current.At this, above-mentioned target lamp electric current depends on the voltage of above-mentioned discharge lamp (Ld), becomes the value of regulation electric power based on the electric power that drops into to above-mentioned discharge lamp (Ld).But after just starting, the voltage of above-mentioned discharge lamp (Ld) is low, rated electrical can not be provided, and therefore, above-mentioned target lamp electric current is controlled as and is no more than the certain limit value that is called as the initial limit electric current.Along with the rising of temperature, the voltage of above-mentioned discharge lamp (Ld) rises then, becomes below the above-mentioned initial limit electric current if the electric power of regulation drops into necessary electric current, then changes the state that can realize that afore mentioned rules electric power drops into swimmingly into.

Fig. 4 shows an example of the converter (Ui) that can use in the lighting apparatus for discharge lamp of the present invention with simplifying.The full-bridge circuit of converter (Ui) switch element (Q1, Q2, Q3, Q4) by having used FET etc. constitutes.Each switch element (Q1, Q2, Q3, Q4) gate driver circuit (G1 by separately, G2, G3, G4) drive, utilization is by the convertor controls signal (Sf1 of inverter drive circuit (Uc) generation of converter, Sf2) by gate driver circuit (G1, G2, G3, G4) come control switch element (Q1, Q2, Q3, Q4), so that above-mentioned gate driver circuit (G1, G2, G3, when the above-mentioned switch element (Q1) of the side diagonal angle key element G4) and above-mentioned switch element (Q3) are in the phase place of conducting state, the above-mentioned switch element (Q2) and the above-mentioned switch element (Q4) of the opposing party diagonal angle key element are kept off-state, on the contrary, when the above-mentioned switch element (Q2) of the opposing party diagonal angle key element and above-mentioned switch element (Q4) were in the phase place of conducting state, the above-mentioned switch element (Q1) and the above-mentioned switch element (Q3) of a side diagonal angle key element were kept off-state.When carrying out the switching of 2 above-mentioned phase places, insert above-mentioned switch element (Q1, Q2, Q3, Q4) all become off-state be called as the dead time (dead time) during.

In addition, at above-mentioned switch element (Q1, Q2, Q3, Q4) be under the situation of for example MOSFET, built-in in element self is the parasitic diode (omitting diagram) of suitable direction to drain terminal from source terminal, under the situation of the such element that does not have above-mentioned parasitic diode of bipolar transistor, when above-mentioned phase place is switched, perhaps during the dead time, the caused induced current of inductance composition that can flow and exist by back level at converter (Ui), exist thus because of the danger that back voltage makes the element breakage takes place, therefore, preferred reverse parallel connection is equivalent to the diode of above-mentioned parasitic diode.Drive above-mentioned switch element (Q1, Q2, Q3, Q4) by having received from the inverter drive circuit (Uc) of the signal of the above-mentioned converter drive signal (Sj) of above-mentioned cycle drive circuit (Uj) output.

Fig. 5 is the schematic diagram of waveform of a mode of the embodiment of expression lighting apparatus for discharge lamp of the present invention.This figure is the example that the condition with 3 resonance makes the situation of the lighting apparatus for discharge lamp action that Fig. 1 put down in writing, (a) represent the voltage between terminals of above-mentioned resonant capacitor (Ch), (b) state of the above-mentioned converter drive signal of expression (Sj), during 1 cycle of above-mentioned converter drive signal (Sj) in (Ti), the vibration in 3 cycles takes place in the voltage between terminals of above-mentioned resonant capacitor (Ch) as can be known.It is the resonance frequency of resonant circuit (Nh) and the identical situation of frequency of above-mentioned converter (Ui) that the present invention is not limited only to first-harmonic resonance, can be applicable to that also higher order resonances is the situation of the condition of one of odd number of points of the frequency of above-mentioned converter (Ui) resonance frequency that becomes resonant circuit (Nh).

Fig. 6 is the schematic diagram of characteristic of a mode of the embodiment of expression lighting apparatus for discharge lamp of the present invention.Transverse axis is the driving frequency of converter, and the longitudinal axis is the output voltage (Vnh) that applies to above-mentioned discharge lamp (Ld).From first-harmonic resonance frequency (f0), 3 resonance frequencys (f0/3), 5 resonance frequencys (f0/5), the higher order resonances number of times is high more, the value of above-mentioned output voltage (Vnh) has the tendency of reduction, but can obtain resonance effect by driving transducer (Ui) when the resonance frequency of each odd number time.

By obtaining the strongest resonance, thereby can expect that high voltage is as above-mentioned output voltage (Vnh) with first-harmonic resonance frequency (f0) driving transducer (Ui).Yet, the limit based on the possible frequency of the action of above-mentioned converter (Ui), the i.e. restriction of the upper limiting frequency of the restriction of the driving frequency that causes based on grid capacitance value and resistance, above-mentioned inverter drive circuit (Uc) by above-mentioned switch element (Q1, Q2, Q3, Q4), under the situation that can not drive with high first-harmonic resonance frequency (f0), by utilizing above-mentioned higher order resonances, can evade this restriction.

Fig. 7 is the time diagram of simplification of a mode of the embodiment of lighting apparatus for discharge lamp of the present invention, Fig. 7 has represented the action of the lighting apparatus for discharge lamp that above-mentioned Fig. 1 is illustrated, has represented to detect for the tuning of the above-mentioned resonant circuit (Nh) that carries out above-mentioned converter (Ui) sequence of optimal mapping device frequency.At first, said frequencies control circuit (Uf) changes between this lower limit and higher limit by making said frequencies control signal (Sf), promptly carry out scanning motion, thereby begin till lower frequency limit, to scan the frequency of oscillation of above-mentioned cycle drive circuit (Uj) from upper limiting frequency.Certainly, also can begin to upper limit frequency scanning from lower frequency limit conversely, in addition, also be not limited only to continuous scanning, also can scan to phasic Chang.

Scanning motion has been shown among Fig. 7 has begun till (tj) constantly, begun the situation of scanning said frequencies control signal (Sf) till the lower frequency limit respective value (Sfmin) from upper limiting frequency respective value (Sfmax) from constantly (ti).At this moment, the width of the frequency range from the upper limiting frequency to the lower frequency limit should be set at the width that comprises with the difference of the corresponding resonance frequency of supposition difference of the electrostatic capacitance of the inductance of above-mentioned resonant inductor (Lh) and above-mentioned resonant capacitor (Ch).

Said frequencies control circuit (Uf) monitors above-mentioned tuning degree signal (Sn) when carrying out scanning motion, the formation condition of the said frequencies control signal (Sf) when (th) constantly when storing this signal indication minimum value (Snmin).By like this, can store the driving frequency and resonance (first-harmonic resonance or the higher order resonances) state that condition is roughly consistent of above-mentioned converter (Ui).And, after scanning motion finished, said frequencies control circuit (Uf) was as long as the formation condition of the said frequencies control signal (Sf) during to the roughly consistent state of the driving frequency of above-mentioned converter (Ui) and resonance (first-harmonic resonance or higher order resonances) condition reproduces and fixes.

In addition, constantly (ti) with the upper limit frequency drives during above-mentioned converter (Ui), about begin to move the reason of describing then from the low state of above-mentioned tuning degree signal (Sn) with rising, though this be since the initial upper limiting frequency comparison of setting near the first-harmonic resonance frequency, along with scanning motion can depart from this frequency.And, along with further carrying out of scanning motion, soon above-mentioned tuning degree signal (Sn) reaches very big, then, along with near 3 resonance frequencys, above-mentioned tuning degree signal (Sn) descends, with 3 roughly consistent above-mentioned moment (th) of resonance frequency, above-mentioned tuning degree signal (Sn) is represented minimum.(under the initial situation of upper limiting frequency away from the first-harmonic resonance frequency of setting, rising, very big does not appear in above-mentioned above-mentioned tuning degree signal (Sn).)

Yet, in the process of scanning motion, at the above-mentioned moment (th), when lighting apparatus for discharge lamp has been obtained the little value of above-mentioned tuning degree signal (Sn), if there is not other any information, till the moment (tj) that (Tm) finishes during the scanning motion of the frequency range of being scheduled to above-mentioned, this value that can not judge rightly is a minimum.But, under 2 later situations after for example this optimum frequency detection sequence is the lighting apparatus for discharge lamp energising, if quote the information of the formation condition of the said frequencies control signal (Sf) that in this sequence of last time, obtains, the value of above-mentioned tuning degree signal (Sn) etc., then can omit surpassed after (th) constantly during the scanning motion of remaining period of (Tm).In addition, after 2 times, can quote above-mentioned information, reduce the sweep limits from the upper limiting frequency to the lower frequency limit.

Promptly, when having obtained the little value of above-mentioned tuning degree signal (Sn) in the above-mentioned moment (th), perhaps detect this value then when rising slightly, the situation of the formation condition of obtained said frequencies control signal (Sf) in formation condition this sequence as if the said frequencies control signal (Sf) that can confirm the above-mentioned moment (th) near last time, perhaps can confirm the situation of the value of above-mentioned tuning degree signal (Sn) obtained in this sequence near last time, then the formation condition of the said frequencies control signal (Sf) by the above-mentioned moment (th) can be judged as and detect best converter frequency.

As mentioned above, in the embodiments of the invention of Fig. 1, adopted the formation of the optimum frequency when detecting and being set in above-mentioned converter (Ui) and driving above-mentioned resonant circuit (Nh), compared with the past, do not need the above-mentioned output voltage detecting unit that needs the high voltage tolerance in the past, on resonant inductor the formation of configuration 2 windings etc., especially can obtain the advantage of cost degradation.Specifically, use the mounted on surface resistance of (1608 size) of 1.6mm * O.8mm as above-mentioned resistance (Rr), use the mounted on surface diode of 2.0mm * 1.2mm (2012 size) as above-mentioned diode (Dr), can realize the circuit that above-mentioned optimum frequency when driving above-mentioned resonant circuit (Nh) detects with low-down cost.

Fig. 8 is the time diagram of simplification of a mode of the embodiment of expression lighting apparatus for discharge lamp of the present invention, uses this Fig. 8 to further specify.(a) of this figure represents the waveform of the voltage (Vnh) of generation in the above-mentioned resonant circuit (Nh), (b) waveform of the above-mentioned supply power voltage detection signal of expression (Sv), (c) waveform of expression said frequencies control signal (Sf).About the action of the lighting apparatus for discharge lamp in (Tm) during the scanning motion described in the figure, as above-mentioned about as described in the explanation of Fig. 7.In order in above-mentioned resonant circuit (Nh), to produce strong resonance phenomena, need correctly determine frequency control signal (Sf).Yet because the time delay of the evaluation processing of tuning degree signal (Sn) etc., the restriction relevant with the resolution of said frequencies control circuit (Uf) etc., the frequency control signal of existence (Si) departs from optimum value and possibility that quilt is determined slightly.In addition, even after said frequencies control signal (Sf) decision, by in the above-mentioned resonant circuit (Nh) that comprises above-mentioned resonant inductor (Lh) and above-mentioned resonant capacitor (Ch), flowing through electric current, these circuit elements can generate heat, this result, the inductance or the electrostatic capacitance of these circuit elements change, and deviation appears in resonance frequency, exist the frequency control signal (Si) that is determined to depart from the possibility of optimum value slightly thus.

For fear of such phenomenon, during the above-mentioned scanning motion of (Tm) finish, after the optimum value decision of said frequencies control signal (Sf), in the narrow range of the optimum value of the said frequencies control signal (Sf) that determines comprising, it is resultful continuing to make the action (action that improves or reduce continuously) of said frequencies control signal (Sf) swing.By such action, even the value in the said frequencies control signal (Sf) that is determined departs from optimum value slightly, perhaps resonance frequency is sent out under the situation of variation and so on, by in the whole narrow range that comprises said frequencies control signal (Sf), continuing the scanning motion This move, must realize best said frequencies control signal (Sf) with high frequency, even departed from best said frequencies control signal (Sf) during, because this bias is small, as described in Figure 19 (a), can not produce the voltage decline that the resonance starting of above-mentioned discharge lamp (Ld) is reached harmful degree yet.

Therefore, even there is error in the value in the corresponding said frequencies control signal of resonance frequency (Sf) of the above-mentioned resonant circuit (Nh) that is determined with scanning motion, perhaps exist under the situation of the deviation that causes resonance frequency by the variations in temperature of resonant circuit components, also can guarantee the voltage that applies of lamp is fully raise.In addition, because of the above-mentioned discharge lamp of high voltage (Ld) of resonant circuit (Nh) has begun discharge, enter next step lighting sequence thus, for example wait for from glow discharge after the step of the transformation of arc discharge, even the situation of interruption takes place in the discharge of above-mentioned discharge lamp (Ld), because the optimum value of having stored said frequencies control signal (Sf), can make resonant circuit generation resonance phenomena once more and return at once lamp is applied high-tension state, in addition, because such action can be tried repeatedly, therefore can reduce significantly to be absorbed in and light failed probability.

In Fig. 8, the optimum frequency of the value that is used to determine said frequencies control signal (Sf) detect sequence during exist idle period of time to describe between moment (tc) of beginning of the output of finish time (tj) of (Tm) and above-mentioned output voltage (Vnh) (Tn), the length of (Tn) or have or not to set and get final product during this period by the service condition of lighting apparatus for discharge lamp.For example, when lighting, inserts by each lamp under the situation of mode that above-mentioned optimum frequency detects sequence, can make above-mentioned idle period of time (Tn) very short, be not set during this period (length of (Tn) is made as zero getting final product during inciting somebody to action) especially in case of necessity perhaps.

When the energising of lighting apparatus for discharge lamp, implement above-mentioned optimum frequency and detect sequence, the formation condition of storage said frequencies control signal (Sf), then, for example accepted that lamp is lighted instruction and lamp is lighted before sequence begins at the projector body that lighting apparatus for discharge lamp is installed internally, reproduce and be suitable for the formation condition of the said frequencies control signal (Sf) of being stored, under the situation that has adopted this mode, only be equivalent to optimum frequency detect sequence during (Tm) during, can realize lighting the saving of time of instruction beginning till actual lamp is lighted from receiving above-mentioned lamp.But, under the situation of this mode, though above-mentioned idle period of time, (Tn) was elongated, but if become long during this period, for example, generation variations in temperature in the during this period and deviation of resonance frequency as described above becomes excessive, the driving frequency of the above-mentioned converter of result (Ui) and the deviation of resonance frequency become excessive, may there be the caused voltage of the resonance inadequate problem that becomes that raises, methods such as therefore preferred enforcement is following, for example, during idle period of time has passed through necessarily, implement above-mentioned optimum frequency and detect sequence, thereby upgrade the storage of the formation condition of said frequencies control signal (Sf); Perhaps, passed through in idle period of time and to begin lamp after above during certain and light under the situation of sequence, the above-mentioned optimum frequency detection sequence of enforcement etc. before being about to the bright sequence of starting point.

As mentioned above, when lighting, inserts by each lamp under the situation of mode that above-mentioned optimum frequency detects sequence, above-mentioned idle period of time (Tn) is not existed, during this period can realize the saving of time because of omitting, in addition, as before about the explanation of Fig. 7, for example optimum frequency detects under the situation that sequence is the 2nd later optimum frequency detection sequence after the lighting apparatus for discharge lamp energising, can quote the formation condition of the said frequencies control signal (Sf) that in this sequence of last time, obtains, the information of the value of above-mentioned tuning degree signal (Sn), omit surpassed constantly (th) afterwards during the scanning motion of remaining period of (Tm).In Fig. 9, illustrate the action of the lighting apparatus for discharge lamp under such situation.At the moment that has surpassed the above-mentioned moment (th) (tn), the optimum frequency of quoting last time detects obtained above-mentioned information in the sequence, can be judged as and detect optimum frequency, begins the output of above-mentioned output voltage (Vnh) immediately.

Figure 10 is the flow chart of simplification of a mode of the embodiment of expression lighting apparatus for discharge lamp of the present invention, uses this Figure 10 further to describe.This figure be constituted comprising microprocessor unit under the situation of said frequencies control circuit (Uf), about a example based on the flow chart of the microprocessor program of the part of the illustrated action of Fig. 7.

Tuning degree signal variable (Dsn) is to be used for the variable of temporary transient storage with the value after above-mentioned tuning degree signal (Sn) the AD conversion.Minimum tuning degree signal variable (DsnMin) be used for temporarily being kept at optimum frequency detect sequence executory, at the variable of the minimum from processing block described later (B12) the above-mentioned tuning degree signal (Sn) obtained to the circulation of processing block (B24).Frequency control signal variable (Dsf) is used for the variable of temporary transient storage to the value of frequency control signal (Sf) setting.FREQUENCY CONTROL optimum value variable (DsfOptim) is used to save as the variable as the candidate of the value optimum value that said frequencies control signal (Sf) is set.In addition, be under the situation of analog signal in said frequencies control signal (Sf), said frequencies control signal variable (Dsf) or said frequencies control optimum value variable (DsfOptim) are carried out exporting after the DA conversion.

Detecting end mark (F_Valid) is that the above-mentioned optimum frequency of expression detects the sign that sequence has finished.Be masked as under the situation of vacation (false) at this, by the judgement in the processing block (B21), carry out later optimum frequency and detect sequence, be masked as under the situation of very (true) at this, owing to stored the formation condition of said frequencies control signal (Sf), therefore do not carry out optimum frequency and detect sequence, begin the output of above-mentioned output voltage (Vnh) immediately.

In processing block (B10), carry out the initial setting before optimum frequency detection sequence is performed.Above-mentioned minimum tuning degree signal variable (DsnMin) is set at the maximum or the above value of this maximum that can obtain as above-mentioned tuning degree signal variable (Dsn).For example, under the data width of above-mentioned tuning degree signal (Sn) during by the AD conversion is 10 situation, it is made as 1023 gets final product, perhaps, the data width of above-mentioned tuning degree signal variable (Dsn) at this moment is under 16 the situation, and being set is 65535 to get final product.In addition, said frequencies control signal variable (Dsf) is set to the upper limiting frequency respective value (Sfmax) of the driving frequency that is used to scan.

Then, in processing block (B12), be taken into above-mentioned tuning degree signal (Sn) as data and be kept in the tuning degree signal variable (Dsn).After the initial setting in just having carried out above-mentioned processing block (B10), because frequency control signal (Sf) is set to upper limiting frequency respective value (Sfmax), converter (Ui) moves with upper limiting frequency, is taken into the above-mentioned tuning degree signal (Sn) of this moment.The driving frequency of converter (Ui) is updated in processing block described later (B14), and scanning motion is performed thus, when returning this processing block (B12), is taken into above-mentioned tuning degree signal (Sn) and it is kept in the tuning degree signal variable (Dsn).

In processing block (B23), judge that whether obtained than the past above-mentioned tuning degree signal variable (Dsn) minimum tuning degree signal variable (DsnMin) low, if be judged as be, then carry out processing block (B13), present tuning degree signal variable (Dsn) is saved in the minimum tuning degree signal variable (DsnMin), and present frequency control signal variable (Dsf) is saved in the FREQUENCY CONTROL optimum value variable (DsfOptim),, does not then carry out above-mentioned processing block (B13) if be judged as not.

Then, in processing block (B14),, reduce frequency control signal variable (DSf) and it is set in the said frequencies control signal (Sf) in order to carry out scanning motion to lower frequency limit respective value (Sfmin) from upper limiting frequency respective value (Sfmax) beginning.The driving frequency of above-mentioned thus converter (Ui) is updated.Then, in processing block (B24), whether determination frequency control signal variable (DSf) reaches lower frequency limit respective value (Sfmin), if reach, then finish scanning motion, advance to processing block (B15), if do not reach, then be back to above-mentioned processing block (B12), proceed scanning motion.

In processing block (B15), the detection end mark (F_Valid) that expression optimum frequency detection sequence has been finished is true (true).The value of the FREQUENCY CONTROL optimum value variable of storing in the above-mentioned processing block of nearby carrying out at this moment, (B13) (DsfOptim) is decided to be the corresponding optimum value of driving frequency with above-mentioned converter (Ui).In the processing block (B16) after the optimum frequency that is through with detects sequence, in said frequencies control signal (Sf), set the FREQUENCY CONTROL optimum value variable (DsfOptim) of detected the best, the driving frequency of above-mentioned converter (Ui) is set at the frequency of the best.If leave this program, then power supply circuits are exported above-mentioned output voltage (Vnh), proceed to light starting sequence.

Figure 11 is the block diagram of another mode that simplifies the embodiment of ground expression lighting apparatus for discharge lamp of the present invention.In the execution mode of above-mentioned Fig. 1, obtain above-mentioned tuning degree signal (Sn) from the series circuit of above-mentioned resistance (Rr) and above-mentioned diode (Dr), and in the execution mode of Figure 11, constitute, above-mentioned supply power voltage detecting unit (Vx) double as in the above-mentioned power supply circuits (Ux) is an above-mentioned tuning degree detecting unit (Un), and above-mentioned supply power voltage detection signal (Sv) double as is an above-mentioned tuning degree signal (Sn).As illustrated with reference to above-mentioned Fig. 2 or Fig. 7, detect in the sequence in optimum frequency, to the driving frequency of above-mentioned converter (Ui) more near resonance frequency, the current potential of the node (T21) of the voltage input of above-mentioned converter (Ui) is low more, thereby the low more phenomenon of current potential of above-mentioned tuning degree signal (Sn) detects, and replace above-mentioned tuning degree signal (Sn), can reach identical purpose to detecting also with the phenomenon of the current potential step-down of the corresponding above-mentioned supply power voltage detection signal of output voltage (Sv) of the above-mentioned power supply circuits (Ux) of the input voltage that is equal to above-mentioned converter (Ui).

Using microprocessor, digital signal processor, add above-mentioned power-supplying circuit (Fx), said frequencies control circuit (Uf), above-mentioned cycle drive circuit (Uj) waits under the situation of the signal processing control circuit that constitutes one, the mode that is taken into above-mentioned signal processing control circuit with above-mentioned supply power voltage detection signal (Sv) and above-mentioned tuning degree signal (Sn) as signal is independently compared, such shown in the execution mode of Figure 11, (for example AD conversion) is taken into this signal as 1 signal, realization in above-mentioned signal processing control circuit comprises that the position of each function of the processing capacity of lamp electric power control etc. and the processing capacity that optimum frequency detects sequence utilizes the mode of this signal, owing to can save the input port of signal, therefore the use of the element resources of AD conversion passage etc. helps cost degradation more.

But, as mentioned above, the voltage that the above-mentioned constant voltage source of voltage ratio (Up) that above-mentioned power supply circuits (Ux) are produced is produced is high a lot, therefore compare with above-mentioned tuning degree signal (Sn) among above-mentioned Fig. 1, the dynamic range of the signal of above-mentioned supply power voltage detection signal (Sv) is bigger, and the system that measures this signal should be noted that to possess the great dynamic range that is complementary with it.Otherwise, according to the microprocessor that constitutes lighting apparatus for discharge lamp, the situation of digital signal processor, if the dynamic range of above-mentioned supply power voltage detection signal (Sv) can not obtain enough big scope, be not enough to detect tuning to the resonance frequency of the driving frequency of above-mentioned converter (Ui), then the execution mode of Fig. 1 more favourable in this case.

Figure 12 is the block diagram of a mode that further simplifies the embodiment of ground expression lighting apparatus for discharge lamp of the present invention.In the execution mode of above-mentioned Figure 11, above-mentioned converter (Ui) is via above-mentioned resistance (Rr), move from accepting the certain power supply of supply capacity with DC power supply (Vcc) as the above-mentioned control circuit of above-mentioned constant voltage source (Up), and in the execution mode of Figure 12, abandon supplying with via the electric power from above-mentioned constant voltage source (Up) of above-mentioned resistance (Rr), detect in optimum frequency sequence above-mentioned at least converter (Ui) scanning motion during, above-mentioned power supply circuits (Ux) carry out the certain action of supply capacity.

In addition, method as the certain action of the supply capacity that realizes above-mentioned power supply circuits (Ux), straightforward procedure is as follows: for example, the load cycle ratio that will constitute the above-mentioned switch element (Qx) of above-mentioned power supply circuits (Ux) is controlled to be the method that roughly necessarily generates above-mentioned gate drive signal (Sg); Perhaps, the output current with above-mentioned power supply circuits (Ux) is controlled to be the method that roughly necessarily generates above-mentioned gate drive signal (Sg).Like this in above-mentioned converter (Ui) course of action, constitute above-mentioned power supply circuits (Ux) and carry out the certain action of supply capacity, thus with identical with reference to the explanation that above-mentioned Fig. 2 or Fig. 7 carried out, detect in the sequence in optimum frequency, the driving frequency of above-mentioned converter (Ui) is more near resonance frequency, the current potential of the node (T21) of the voltage input of above-mentioned converter (Ui) is low more, the current potential of above-mentioned supply power voltage detection signal (Sv) is low more, thereby can detect optimum frequency by this phenomenon is detected.

But, as described above the load cycle ratio of above-mentioned switch element (Qx) is being controlled to be roughly certain or the output current of above-mentioned power supply circuits (Ux) is being controlled to be roughly one regularly, for example monitor above-mentioned supply power voltage detection signal (Sv), this voltage and above-mentioned control circuit are quite and relatively low with DC power supply (Vcc), more specifically, as before with reference to above-mentioned Fig. 2 illustrated, must make this voltage be no more than the voltage of regulation, can not take place so that in the above-mentioned discharge lamp (Ld) that connects, produce the high resonance potential of insulation breakdown, and, surpassed at this voltage under the voltage condition of afore mentioned rules, must stop the generation of above-mentioned gate drive signal (Sg).Figure 13 is the time diagram of simplification of a mode of expression lighting apparatus for discharge lamp of the present invention, uses this Figure 13 to further specify.This figure is that the condition with 3 resonance makes lighting apparatus for discharge lamp action shown in Figure 1, start by resonance under the situation of above-mentioned discharge lamp (Ld), the example of the waveform that in adjusting stage of starting sequence etc., may observe, (a) waveform of the lamp current (IL) of above-mentioned discharge lamp (Ld) is flow through in expression, (b) waveform of the above-mentioned converter drive signal of expression (Sj), (c) represent the appearance of variation of the frequency (f) of above-mentioned converter (Ui), expression all be (tc) the later action of the above-mentioned moment shown in above-mentioned Fig. 8.But, omit record with reference to the content that above-mentioned Fig. 8 had illustrated, promptly in the narrow range of the optimum value that comprises said frequencies control signal (Sf), make the action of said frequencies control signal (Sf) swing.

By the resonance starting, in the moment (tz), insulation breakdown takes place and begin streaming current in above-mentioned discharge lamp (Ld) in above-mentioned discharge lamp (Ld).Electric current takes place after the insulation breakdown only to a side direction of electrode for discharge lamp mobile asymmetric electric discharge phenomena, glow discharge, in the glow discharge generating process, as Zener diode, lamp two interelectrode voltages become lamp discharge condition intrinsic voltage, and because lamp consumes electric power, the Q value of above-mentioned resonant circuit (Nh) becomes low-down state, and the voltage rising that is caused by resonance can take place hardly.

Figure 13 has represented that above-mentioned discharge lamp (Ld) is in the state of asymmetric discharge, in (a) of this figure, shows lamp current (IL) multithread to positive side direction as an example, seldom flows to the situation of minus side direction.The positive side direction that such waveform observes easily at lamp current (IL) produces arc discharge, produces the situation of glow discharge in the minus side direction.Even lamp current is little during glow discharge, because modulating voltage height, in the discharge space of lamp cation be accelerated into high-energy and with the collision of the cathode electrode of lamp, therefore, between if glow discharge continues for a long time, then because sputter and electrode materials such as tungsten spill and be attached to the inner surface of lamp vacuum tube to discharge space, thereby produce the problem of the melanism of lamp.Therefore, during so asymmetric discharge, make lamp current flow more and the heating promotion electrode, it is favourable changing arc discharge into from glow discharge apace.

As above-mentioned shown in Figure 13, the starting stage at least in the starting sequence of lamp, the promptly typical roughly state of a control of the voltage about 200V of described non-loaded open voltage (Vop) before the output of above-mentioned power supply circuits (Ux) need be maintained and can export.This is because need to keep the glow discharge of lamp.Before, illustrated if glow discharge continue long-term between then lamp produce the problem of melanism, but if glow discharge all can not be kept, meeting guiding discharge electric current stops and interrupting.Another reason is, driving frequency at above-mentioned converter (Ui) is under the situation of for example 100kHz, because this frequency is a high frequency, the impedance of above-mentioned resonant inductor (Lh) also uprises, therefore, in order to keep this arc discharge, as the voltage that is connected in series and applies to above-mentioned discharge lamp (Ld) and above-mentioned resonant inductor (Lh), the voltage of above-mentioned degree is necessary after changing arc discharge into.

Illustrated that before to change arc discharge into from glow discharge fast more favourable,, for example, can consider further to improve non-loaded open voltage, the method during increase glow discharge the input electric power of lamp as the method for this mode of realization.But in order to realize this method, the above-mentioned switch element of above-mentioned converter (Ui) (Q1, Q2, Q3, Q4) must be and the element of the high corresponding high withstand voltage of non-loaded open voltage that applies, therefore be unfavorable for cost degradation.

Therefore, make lamp current flow more and the heating promotion electrode in during asymmetric discharge, making the glow discharge fast transition is the residue scheme of arc discharge, judges the high impedance that needs to reduce above-mentioned resonant inductor (Lh).Originally, if the starting sequence of lamp finishes, then above-mentioned converter (Ui) driving frequency finally changed the low frequency about frequency 50Hz～400Hz when above-mentioned discharge lamp (Ld) is stable to be lighted into.Therefore, in the moment that the transformation to low frequency finishes, the high problem of impedance of above-mentioned resonant inductor (Lh) that may be above-mentioned can naturally and understandably be resolved.

But, for example become suddenly under the situation of above-mentioned low frequency near the 100kHz at the driving frequency of above-mentioned converter (Ui) high frequency when resonance starts, flow through superfluous impulse current to above-mentioned discharge lamp (Ld) sometimes.This be because, be accompanied by the rapid decline of the frequency of above-mentioned converter (Ui), the impedance of above-mentioned resonant inductor (Lh) sharply descends, and, flow through the result of impulse current as above-mentioned discharge lamp (Ld), the impedance of above-mentioned discharge lamp (Ld) self descends, therefore can not with the control servo-actuated of above-mentioned power supply circuits (Ux), the positive feedback of flowing through the electric current of above-mentioned discharge lamp (Ld) increases and can take place moment, may be to above-mentioned discharge lamp (Ld) thereby can produce, above-mentioned switch element (the Q1 of above-mentioned converter (Ui), Q2, Q3, Q4) or the problem that damages such as the above-mentioned switch element (Qx) of above-mentioned power supply circuits (Ux).

In addition, in the state of the asymmetric discharge of above-mentioned discharge lamp (Ld), for above-mentioned electrode (E1, in E2) can arc discharge in the circulation that becomes negative electrode a lateral electrode, if do not promote heating so that it can begin to emit hot electron, then can not eliminate the state of asymmetric discharge.In such state, in a circulation of the AC driving of above-mentioned converter (Ui), the input electric power of lamp is most circulated and the smaller part circulation repeatedly, and in during the input electric power of lamp little semi-cyclic, hot electron is emitted a lateral electrode temperature that does not begin and is descended.If the driving frequency of above-mentioned converter (Ui) sharply changes to low frequency under the state that the state of asymmetric discharge is not eliminated, then each semi-cyclic time is sharply elongated, therefore, in half little cycle period of elongated input electric power to lamp, hot electron is emitted a lateral electrode temperature that does not begin and is reduced superfluously, and above-mentioned discharge lamp (Ld) can not be kept the possibility of discharging and taking place to interrupt and uprise.

Look back described content so far as can be known, in the starting sequence of lamp, in the driving frequency that makes above-mentioned converter (Ui) when the low frequency that final above-mentioned discharge lamp (Ld) is stable when lighting changes, be not change frequency sharp, but the high frequency that need comprise when resonance starts begin little by little to reduce the step of frequency at the interior low frequency that finally changes into.

In Figure 13, described at (tz) above-mentioned discharge lamp (Ld) constantly and insulation breakdown has taken place and begin after above-mentioned discharge lamp (Ld) streaming current, said frequencies control signal (Sf) is descended continuously, so that the elongated gradually mode of cycle that the polarity inversion of above-mentioned converter (Ui) takes place makes the appearance of above-mentioned converter (Ui) action.(a) waveform that the above-mentioned lamp electricity in is dredged (IL) is expressed as the waveform of Sawtooth waves shape synchronously in the mode of the above-mentioned converter drive signal (Sj) in (b) being carried out integration, and the current waveform of (Tp) during the representative is wherein carried out simple declaration.

The positive side (upside among the figure) of the above-mentioned lamp current (IL) among the figure (a) is corresponding with the direction that arc discharge produces.For example, the input voltage of supposing above-mentioned converter (Ui) is that the output voltage of above-mentioned power supply circuits (Ux) is 200V, the arc-over voltage of above-mentioned discharge lamp (Ld) is 20V, and the voltage that then above-mentioned lamp current (IL) is applied in above-mentioned resonant inductor (Lh) is speed that inductance value the calculated increase of the voltage difference of 200V and 20V divided by above-mentioned resonant inductor (Lh).Owing to compare with the output voltage of above-mentioned power supply circuits (Ux), arc-over voltage is little a lot, therefore the peak value of the waveform of the Sawtooth waves shape of above-mentioned lamp current (IL) is roughly proportional with the output voltage of above-mentioned power supply circuits (Ux), perhaps proportional with the semi-cyclic time of above-mentioned converter (Ui).Therefore, if the output voltage of above-mentioned power supply circuits (Ux) increases, the maximum of then above-mentioned lamp current (IL) also increases, if the cycle of above-mentioned converter (Ui) increases, the maximum of then above-mentioned lamp current (IL) also increases.

In half circulation of the direction streaming current of the positive side in figure of above-mentioned converter (Ui), alternate repetition is carried out following actions: on one side accumulate magnetic energy above-mentioned lamp current (IL) is increased to above-mentioned resonant inductor (Lh) on one side, from above-mentioned converter (Ui) via resonant inductor (Lh) to above-mentioned discharge lamp streaming current, make above-mentioned lamp current (IL) minimizing if above-mentioned converter (Ui) polarity inversion on one side then discharges the magnetic energy that is accumulated in the above-mentioned resonant inductor (Lh).Like this, descend continuously towards low frequency by the driving frequency that makes above-mentioned converter (Ui), the lowest high-current value of above-mentioned lamp current (IL) can increase gradually, therefore, for a lateral electrode that in the circulation that becomes negative electrode, does not become arc discharge, it is heated in promotion so that it can begin to emit hot electron, thereby eliminates the state of asymmetric discharge, obtains to prevent the effect of interrupting.

Yet, during this figure in (Tq), the waveform of above-mentioned lamp current (IL) with above-mentioned during desirable Sawtooth waves shape in (Tp) different, near this peak value, flow through super-high-current, and the driving frequency of above-mentioned converter (Ui) is low more, and this super-high-current is big more.This be because, above-mentioned lamp current (IL) has surpassed the saturation limit current value (Ih) of above-mentioned resonant inductor (Lh), thus the driving frequency of above-mentioned converter (Ui) is low more, surpass above-mentioned saturation limit current value (Ih) during long more.

Figure 14 is the time diagram of simplification of a mode of the embodiment of expression lighting apparatus for discharge lamp of the present invention, uses this Figure 14 to further specify.(a) among this figure represents the waveform of the voltage (Vnh) that produced in the above-mentioned resonant circuit (Nh), (b) waveform of the above-mentioned power supply circuits output voltage of expression (Vo), (c) represent the waveform of above-mentioned lamp current (IL), (d) represent the appearance of variation of the frequency (f) of above-mentioned converter (Ui).Under the situation that optimum frequency detection sequence has finished, begin the starting sequence of above-mentioned discharge lamp (Ld) in the moment (tr).Because the optimum frequency with the above-mentioned converter (Ui) corresponding with said frequencies control signal (Sf) drives, therefore produce high voltage at once in the above-mentioned output voltage (Vnh).As can be seen in the insulation breakdown of (ts) above-mentioned discharge lamp (Ld) generation constantly, above-mentioned lamp current (1L) has begun to flow, after one section between after during in, be partial to positive side as can be known according to the waveform of above-mentioned lamp current (IL), produced the state of asymmetric discharge.On the other hand, according to the waveform of above-mentioned supply power voltage detection signal (Sv) also as can be known, above-mentioned power supply circuits (Ux) are exported non-loaded open voltage (Vop) always and are offered above-mentioned converter (Ui) from the beginning of starting sequence.

When the moment (tt), as mentioned above, the driving frequency that makes above-mentioned converter (Ui) of the step that descends gradually by the high frequency that comprises when resonance starts changes the sequence of final low frequency into, and as mentioned above, more multithread is moving and promote the heating of electrode to make lamp current.Therefore, the situation of the state-transition that is enhanced to positive and negative balance gradually from the state of being partial to positive side according to the waveform of the above-mentioned lamp current (IL) among Figure 14 as can be known, the state of asymmetric discharge is eliminated gradually.

And, drop to the moment (tu) of the 1st thresfhold frequency (fj1) in the frequency of above-mentioned converter (Ui), the state (voltage mode control) of the non-loaded open voltage (Vop) that control output is so far is disengaged, for example, make above-mentioned supply current detection signal (Si) become the state (current control mode) of desired value ground control in order to switch to, change the control model of above-mentioned power supply circuits (Ux), and till the 2nd thresfhold frequency (fj2), control sharply descends the frequency of above-mentioned converter (Ui).At this, the state (current control mode) that makes above-mentioned supply current detection signal (Si) become the control of desired value ground is meant, before, action described in the explanation of " above-mentioned power-supplying circuit (Fx) flows through under the situation of discharging current in the lamp starting, and feedback ground generates above-mentioned gate drive signal (Sg) so that the export target lamp current ".

By such control, the frequency of above-mentioned converter (Ui) becomes enough low, therefore the impedance of above-mentioned resonant inductor (Lh) is enough low, the voltage of above-mentioned power supply circuits (Ux) becomes the modulating voltage that presented with above-mentioned discharge lamp (Ld) about equally, therefore, the output voltage of above-mentioned power supply circuits (Ux) does not need the such high voltage of non-loaded open voltage.Like this, frequency at above-mentioned converter (Ui) is enough low, in addition, output voltage at above-mentioned power supply circuits (Ux) becomes under the state that enough hangs down the arc-over voltage degree that arrives above-mentioned discharge lamp (Ld), there are not quick variation, the peak value of such above-mentioned lamp current (IL) shown in (a) among above-mentioned Figure 13, by the control that above-mentioned supply current detection signal (Si) is carried out, can correctly control above-mentioned lamp current (IL).Its result, the above-mentioned super-high-current that surpasses the above-mentioned lamp current (IL) that the saturation limit current value (Ih) of above-mentioned resonant inductor (Lh) produces because of above-mentioned lamp current (IL) can be avoided.

In addition, at the above-mentioned moment (tu), owing to switch the frequency of above-mentioned converter (Ui) and the above-mentioned control model of above-mentioned power supply circuits (Ux) simultaneously, because the difference (or deviation (jitter)) of delicate switching timing causes flowing through above-mentioned discharge lamp (Ld) at (tu) impulse current of the above-mentioned moment sometimes.By use Pulse by Pulse (pulse by pulse) control technology limit above-mentioned switch element (Qx) conducting state during length, perhaps, lighting apparatus for discharge lamp self can be controlled the appearance of (tu) constantly, before (tu) is about to occur constantly, desired value setting on the low side with the output voltage or the output current of above-mentioned power supply circuits (Ux), to the method that the length during the conducting state of above-mentioned switch element (Qx) is limited etc., can avoid flowing through the phenomenon of above-mentioned impulse current.

Under the state that has applied non-loaded open voltage, in the orthochronous till saturated to above-mentioned resonant inductor (Lh) beginning, saturated phenomenon is a non-linear phenomena, therefore, as mentioned above, the speed that can not utilize voltage that above-mentioned resonant inductor (Lh) is applied in to calculate divided by this inductance value is merely calculated, above-mentioned the 1st thresfhold frequency (fj1) is obtained and set to the difference of above-mentioned saturation limit current value (Ih) that preferably includes above-mentioned resonant inductor (Lh) interior in the mode of experiment.In above-mentioned Figure 14, show the above-mentioned moment (tu) that drops to above-mentioned the 1st thresfhold frequency (fj1) in the frequency of above-mentioned converter (Ui), the frequency of controlling above-mentioned converter (Ui) drops to the situation of above-mentioned the 2nd thresfhold frequency (fj2) immediately, because the elimination of the state of asymmetric discharge need be up to the above-mentioned electrode (E1 of lamp, E2) time till heat balance is reached, drop to above-mentioned the 2nd thresfhold frequency (fj2) before in the frequency that makes above-mentioned converter (Ui), under the state of above-mentioned the 1st thresfhold frequency (fj1), so that carry out the standby of appropriate time, can increase the reliability of the state elimination of asymmetric discharge by control.

In addition, not to make the frequency of above-mentioned converter (Ui) directly change aforementioned stable ignition frequency (fstb) into from above-mentioned the 1st thresfhold frequency (fj1), but temporarily change earlier above-mentioned the 2nd thresfhold frequency (fj2) into, change aforementioned stable ignition frequency (fstb) then gradually into, this be because, in the moment of the frequency that makes above-mentioned converter (Ui) from the rapid decline of above-mentioned the 1st thresfhold frequency (fj1) beginning, under the unclosed situation of elimination of the state of asymmetric discharge, before the transformation end, the elimination of the state of asymmetric discharge is finished to changing aforementioned stable ignition frequency (fstb) into afterwards from changing above-mentioned the 2nd thresfhold frequency (fj2) into.

Therefore, illustrated in the frequency that makes above-mentioned converter (Ui) before and dropped to above-mentioned the 2nd thresfhold frequency (fj2) before, under the state of above-mentioned the 1st thresfhold frequency (fj1), by controlling so that carry out the mode of the standby of appropriate time, by implementing this mode, perhaps, do not implement this mode, for example, by design thermal capacity lessly so that the above-mentioned electrode (E1 of lamp, E2) heat balance is reached easily, be modes such as the easy rising of temperature, in the moment of the frequency that makes above-mentioned converter (Ui) from the rapid decline of above-mentioned the 1st thresfhold frequency (fj1), under the situation that the elimination of the state of asymmetric discharge has finished, the frequency that also may be controlled to above-mentioned converter (Ui) directly changes (fringe time is zero) from above-mentioned the 1st thresfhold frequency (fj1) and is aforementioned stable ignition frequency (fstb).The time diagram of the simplification of the mode of the appearance of the FREQUENCY CONTROL of the above-mentioned converter (Ui) of this moment such as the embodiment of lighting apparatus for discharge lamp of the present invention is promptly shown in Figure 16.

As mentioned above, based on the discharge of above-mentioned discharge lamp (Ld) heating and the temperature of above-mentioned electrode (E1, E2) rises very importantly, this depends on the electric power that lamp is dropped into, the thermal capacity of electrode.According to the above description as can be known, the electric power that lamp is dropped into is also stipulated by the output voltage of above-mentioned power supply circuits (Ux) not only by the frequency of above-mentioned converter (Ui) is stipulated as the impedance of the above-mentioned resonant inductor (Lh) of parameter.Therefore, about optimum value from the above-mentioned moment (tt) to the length the tour of the above-mentioned moment (tu), the thermal capacity of the output voltage of the above-mentioned power supply circuits (Ux) in depending between this tour, above-mentioned electrode (E1, E2), thereby need obtain by experiment.About optimum value from the above-mentioned moment (tu) to the length the tour of the above-mentioned moment (tv), comprise above-mentioned such fringe time and be zero situation interior, need too to obtain by experiment.In addition, about decrease speed from the frequency of above-mentioned the 2nd thresfhold frequency (fj2) beginning when the low frequency that changes final stable illuminating state into is promptly stablized ignition frequency (fstb), in above-mentioned Figure 14, be described as identically, but also can constitute their decrease speed (slope of above-mentioned supply power voltage detection signal (Sv)) difference with decrease speed from the frequency of the above-mentioned moment (tt) beginning.

Yet, about the above-mentioned establishing method that makes the above-mentioned moment of starting point (tt) of the sequence that the high frequency of above-mentioned converter (Ui) driving frequency when resonance starts begin to reduce gradually, for example the simplest mode is to be set at from the starting point of above-mentioned starting sequence to be the above-mentioned moment (tr), to have passed through the moment after time of specific length.Perhaps, also can be set at from above-mentioned discharge lamp (Ld) and produce moment after above-mentioned moment (ts) that insulation breakdown, above-mentioned lamp current (IL) begin to flow has begun, passed through time of specific length.In addition, also can be set at from above-mentioned lamp current (IL) begin to flow and this current value is increased to the moment (tw) beginning of the value suitable with arc discharge, through the moment after the time of (comprising zero) specific length interior.In addition, can monitor above-mentioned supply current detection signal (Si) from above-mentioned supply current detecting unit (IX), by monitoring that it has surpassed setting and has detected the situation that above-mentioned discharge lamp (Ld) begins to flow, perhaps this current value is increased to the situation of the value suitable with arc discharge.

With (a) in the time diagram of the simplification of the mode of the embodiment of the lighting apparatus for discharge lamp of the present invention shown in above-mentioned Figure 14 and the corresponding waveform of surveying of waveform (c) as shown in figure 15.(a) of this figure is the waveform of the voltage (Vnh) of generation in the above-mentioned resonant circuit of expression (Nh), (c) be the waveform of the above-mentioned lamp current of expression (IL), the moment shown in the figure (tr, ts, tt, tu, tv, tw) is corresponding with the above-mentioned moment shown in above-mentioned Figure 14 (tr, ts, tt, tu, tv, tw) respectively.In fact, above-mentioned Figure 14 (a) and waveform (c) are drawn in the mode of above-mentioned Figure 15 of replication (a) and waveform (c) and are formed.But, in the measured waveform of Figure 15, at beginning of the above-mentioned moment (tr) starting sequence, above-mentioned discharge lamp (Ld) has produced insulation breakdown begin to apply the high voltage that is produced by resonance to above-mentioned discharge lamp (Ld) after, and this above-mentioned moment (ts) that has produced insulation breakdown is too approaching with the above-mentioned moment (tr), for convenience of explanation, in above-mentioned Figure 14, so that elongated mode has been carried out distortion slightly between the above-mentioned moment (tr) and the above-mentioned moment (ts).Between the above-mentioned moment (ts) and the above-mentioned moment (tw) too.

In the embodiment of a mode of the lighting apparatus for discharge lamp of the present invention of the measured waveform of having put down in writing above-mentioned Figure 15, being set as follows of concrete numerical parameter.

Lamp: specified 200W high-pressure mercury-vapor lamp

Non-loaded open voltage (Vop): 200V

Resonance frequency: about 100kHz (3 resonance)

The 1st thresfhold frequency (fj1): 40kHz

The 2nd thresfhold frequency (fj2): 8kHz

Stablize ignition frequency (fstb): 370Hz

During the standby that begins beginning (from constantly (tr) to the moment (tt)) of starting sequence: about 3 seconds to the sequence that frequency is reduced gradually

From the tour of resonance frequency to the 1 thresfhold frequency (from constantly (tt) to the moment (tu)): about 1 second

From the 2nd thresfhold frequency to the tour of stablizing ignition frequency (from constantly (tu) to the moment (tv)): about 1 second

In addition,,, tested, in this scope, obtained good result from 0.2 second to 3 seconds condition as between the tour of resonance frequency to the 1 thresfhold frequency for employed discharge lamp in this actual measurement experiment.

The parameter relevant with embodiments of the present invention that illustrates with reference to above-mentioned Figure 15 etc. goes for following high-pressure mercury-vapor lamp, in this high-pressure mercury-vapor lamp, front end forms bossed pair of electrodes with the interval arranged opposite below the 2.0mm, enclosed every cubic millimeter more than 0.2 milligram mercury and the negative micromolar halogen of 2 powers of micromole～10 of every cubic millimeter 10 negative 6 powers.Observe the waveform of the actual measurement of above-mentioned Figure 15, as illustrated with reference to above-mentioned Figure 14, in the moment (tt), as mentioned above, the step that reduces gradually by the high frequency that comprises when resonance starts is in the sequence that changes final low frequency into of the interior driving frequency that makes above-mentioned converter (Ui), as mentioned above, more multithread is moving and promote the heating of electrode to make lamp current, the situation of the state-transition that is enhanced to positive negative balance gradually from the state of being partial to positive side according to the waveform of above-mentioned lamp current (IL) can be sure of that the present invention has effect for the promotion of the elimination of the state of asymmetric discharge.

As mentioned above, overstep the extreme limit and can produce the phenomenon that above-mentioned lamp current (IL) surpasses the above-mentioned saturation limit current value (Ih) of above-mentioned resonant inductor (Lh) under the situation of step-down in the driving frequency of above-mentioned converter (Ui).The size of above-mentioned saturation limit current value (Ih) depends on character, shape and the volume of the core material that constitutes above-mentioned resonant inductor (Lh), therefore, suppose for example in order to realize the good lamp life-span, the value that existence should be set as above-mentioned the 1st thresfhold frequency (fj1), because must selection can realize the core material of this value, this can produce the problem that the miniaturization and of cost degradation, lighting apparatus for discharge lamp is caused severely restricts.

For fear of this problem, with the action of being undertaken by above-mentioned cycle drive circuit (Uj), generate above-mentioned converter drive signal (Sj) from the mode that begins till reaching the 1st thresfhold frequency (fj1), to reduce gradually with the corresponding frequency of the resonance frequency of above-mentioned resonant circuit (Nh) with the frequency of above-mentioned converter (Ui) concurrently, control above-mentioned power-supplying circuit (Fx) so that the voltage that reduces gradually in the above-mentioned before power supply circuits of voltage (Vo2) (Ux) output that reaches the regulation lower than above-mentioned non-loaded open voltage (Vop) gets final product.This be because, as mentioned above, the semi-cyclic time of the peak value of the electric current of above-mentioned resonant inductor (Lh) and above-mentioned converter (Ui) is proportional, also proportional with the output voltage of above-mentioned power supply circuits (Ux), therefore by such control, process along with the time, the former semi-cyclic time increases, therefore and the output voltage of the latter's power supply circuits is controlled as reduction, and gathering way of the peak value of the electric current of above-mentioned resonant inductor (Lh) compared slack-off with the certain situation of the output voltage of power supply circuits.

The time diagram of the simplification of the mode of the embodiment of this situation such as lighting apparatus for discharge lamp of the present invention is promptly shown in Figure 17.In the drawings, (a) waveform of the above-mentioned power supply circuits output voltage of expression (Vo) (b) is represented the appearance of variation of the driving frequency (f) of above-mentioned converter (Ui).Like this, the output voltage by controlling above-mentioned power supply circuits (Ux) and the driving frequency of above-mentioned converter (Ui), condition for zero hour of the sequence that begins to reduce gradually from the high frequency of the driving frequency above-mentioned moment (tt) beginning, that make above-mentioned converter (Ui) when resonance starts, it is the frequency of above-mentioned non-loaded open voltage (Vop), above-mentioned converter (Ui), with identical with reference to the illustrated situation of above-mentioned Figure 14, thereby can not produce the phenomenon that surpasses above-mentioned saturation limit current value (Ih), can set lower above-mentioned the 1st thresfhold frequency (fj1).

In addition, in above-mentioned Figure 17, the decline that shows the frequency of above-mentioned converter (Ui) begins the timing that the decline with the output voltage of above-mentioned power supply circuits (Ux) begins and is situation simultaneously, but the slower situation of timing that the decline that for example also may be controlled to the output voltage of above-mentioned power supply circuits (Ux) begins, in addition, for example also may be controlled to the situation that the decline that makes the output voltage of above-mentioned power supply circuits (Ux) in the decline process of the frequency of above-mentioned converter (Ui) stops.

As mentioned above, according to the embodiment of the present invention, when the low frequency of the high frequency of the driving frequency that makes above-mentioned converter (Ui) when resonance starts during to stable the lighting of final above-mentioned discharge lamp (Ld) changes, not to make its transformation sharp, but it is descended continuously towards low frequency, the lowest high-current value of above-mentioned thus lamp current (IL) can increase gradually, therefore for a lateral electrode of arc discharge not in the circulation that becomes negative electrode, it can promote heating so that can begin to emit hot electron, thereby eliminate the state of asymmetric discharge, obtain to prevent the effect of interrupting.

At this moment, in order to make above-mentioned lamp current (IL) be no more than the saturation limit current value (Ih) of above-mentioned resonant inductor (Lh), drop to the moment of the 1st thresfhold frequency (fj1) in the frequency of above-mentioned converter (Ui), the state of a control (current control mode) that becomes desired value for the state of a control (voltage mode control) of removing the non-loaded open voltage of output before this and usual practice such as above-mentioned supply current detection signal (Si) is switched, change the control model of above-mentioned power supply circuits (Ux), and control the frequency of above-mentioned converter (Ui) so that it sharply is reduced to the enough low frequency that above-mentioned power supply circuits (Ux) can correctly be controlled the degree of above-mentioned lamp current (IL), i.e. the 2nd thresfhold frequency (fj2), can prevent from thus to flow through excessive peak current, prevent above-mentioned discharge lamp (Ld), above-mentioned power supply circuits (Ux), above-mentioned switch element (the Qx of above-mentioned converter (Ui), Q1, Q2, Q3, Q4) damage.

The circuit put down in writing in this specification constitutes the formation of the minimum limit that is necessity of being provided with for action, function and effect that lighting apparatus for discharge lamp of the present invention is described.Therefore, circuit about explanation constitutes, the detailed item of action, for example, the polarity of signal, the selection of concrete circuit element, append or omit, perhaps based on the chance of starting with of element, based on economically reason and the change of change of carrying out etc. all is executive mode during with the actual design device is prerequisite.

Especially about the functional block of above-mentioned power-supplying circuit (Fx), said frequencies control circuit (Uf), above-mentioned cycle drive circuit (Uj) etc., in the actual formation of lighting apparatus for discharge lamp, not necessarily must exist independently of one another, for example, also the several functions as the software in microprocessor, the digital signal processor in these functional blocks can be realized.In this case, the signal of above-mentioned tuning degree signal (Sn), said frequencies control signal (Sf) etc. is realized as digital signal in microprocessor, the digital signal processor or variate-value, not as the voltage signal or the current signal and existing of simulation, such formation also is a kind of in the mode of the present invention.

In addition, be stored in the nonvolatile memory that has used flash memories etc. with the formation condition of said frequencies control signal (Sf) or as said frequencies control signal (Sf) of digital signal or variate-value etc. or have in the memory of Optical devices side of projector etc. of the communication unit of communicating by letter with lighting apparatus for discharge lamp, and valid expiration date of storage is set, under the situation that has surpassed valid expiration date, removing memory contents also obtains once more, can realize the raising of function and performance by following such design, but such design also is can realize in the scope of the design freedom of lighting apparatus for discharge lamp.

In addition; the each several part that the circuit put down in writing in embodiment as required constitutes append following structure also with the present invention as prerequisite; comprise based on overvoltage; overcurrent; the mechanism of circuit element that is used to protect switch elements such as FET etc. of factor is wanted in the puncture of overheated grade; perhaps; the radiation noise that makes the action of the circuit element that is accompanied by electric supply installation and take place; the noise that reduces the generation of conducted noise or make generation is not to the mechanism of outside output; for example, surge voltage protection circuit; nonlinear resistance; clamp diode (clamp diode); (comprising the Pulse by Pulse mode) current limit circuit; the noise filter choking-winding of general modfel or general mode; noise filter capacitor etc.The circuit mode that the formation of lighting apparatus for discharge lamp of the present invention is not limited in this specification to be put down in writing.

Industrial applicibility

The present invention relates to the improvement be used to the lighting apparatus for discharge lamp of lighting high-intensity discharge lamp, such as can in the such image of projector shows the purposes of the use high-intensity discharge lamps such as Optical devices of usefulness, being utilized.

Claims (3)

1. a lighting apparatus for discharge lamp is used to light discharge lamp (Ld), in this discharge lamp (Ld) arranged opposite a pair of electrode (E1, E2) that is used for main discharge, this lighting apparatus for discharge lamp is characterised in that to have:

Power supply circuits (Ux), (Ld) powers to above-mentioned discharge lamp;

Power-supplying circuit (Fx) is used to control above-mentioned power supply circuits (Ux);

Converter (Ui) is arranged on the back level of above-mentioned power supply circuits (Ux), makes the polarity of voltage counter-rotating that above-mentioned discharge lamp (Ld) is applied;

Cycle drive circuit (Uj) generates converter drive signal (Sj), and this converter drive signal (Sj) is to be used for the cyclical signal that the cycle drives above-mentioned converter (Ui); And

Resonant circuit (Nh), be arranged on the back level of above-mentioned converter (Ui), comprise resonant inductor (Lh) and resonant capacitor (Ch), be used for when above-mentioned discharge lamp (Ld) starts improving service voltage above-mentioned discharge lamp (Ld) by the boosting that is accompanied by resonance phenomena

In the starting sequence of above-mentioned discharge lamp (Ld), above-mentioned cycle drive circuit (Uj) generates the corresponding converter drive signal of resonance frequency (Sj) with above-mentioned resonant circuit (Nh), and

Above-mentioned power-supplying circuit (Fx) is controlled, even so that begin to be accompanied by under the situation that the boosting of the resonance phenomena in the above-mentioned resonant circuit (Nh) disappears in discharge owing to above-mentioned discharge lamp (Ld), the voltage that also makes above-mentioned power supply circuits (Ux) output be enough to keep the discharge of above-mentioned discharge lamp (Ld) is non-loaded open voltage (Vop)

Then, above-mentioned cycle drive circuit (Uj) generates above-mentioned converter drive signal (Sj), so that the frequency of above-mentioned converter (Ui) begins to descend gradually till reaching the 1st thresfhold frequency (fj1) from the frequency corresponding with the resonance frequency of above-mentioned resonant circuit (Nh)

If the frequency of above-mentioned converter (Ui) reaches above-mentioned the 1st thresfhold frequency (fj1), then above-mentioned cycle drive circuit (Uj) generates above-mentioned converter drive signal (Sj), so that the frequency of above-mentioned converter (Ui) becomes stable ignition frequency (fstb), and

Above-mentioned power-supplying circuit (Fx) is controlled so that above-mentioned power supply circuits (Ux) output is enough to keep the electric current of the discharge of above-mentioned discharge lamp (Ld).

2. lighting apparatus for discharge lamp as claimed in claim 1 is characterized in that,

If the frequency of above-mentioned converter (Ui) reaches above-mentioned the 1st thresfhold frequency (fj1), then above-mentioned cycle drive circuit (Uj) inserts following actions in generation above-mentioned converter drive signal (Sj) before so that the frequency of above-mentioned converter (Ui) becomes stable ignition frequency (fstb), promptly, generate above-mentioned converter drive signal (Sj) so that the frequency of above-mentioned converter (Ui) becomes 2nd thresfhold frequency (fj2) lower than above-mentioned the 1st thresfhold frequency (fj1), generate above-mentioned converter drive signal (Sj) then so that the frequency of above-mentioned converter (Ui) drops to aforementioned stable ignition frequency (fstb) gradually.

3. lighting apparatus for discharge lamp as claimed in claim 1 or 2 is characterized in that,

With undertaken by above-mentioned cycle drive circuit (Uj), generate above-mentioned converter drive signal (Sj) so that the frequency of above-mentioned converter (Ui) from beginning the action that till reaching the 1st thresfhold frequency (fj1), descends gradually concurrently with the corresponding frequency of the resonance frequency of above-mentioned resonant circuit (Nh), above-mentioned power-supplying circuit (Fx) is controlled, so that the voltage that above-mentioned power supply circuits (Ux) output descends gradually, till the voltage (Vo2) that reaches the regulation lower than above-mentioned non-loaded open voltage (Vop).

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